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Class ELS.1- 
Book. L3 M + 



OIKM 1A1. DONATION. 



MARYLAND GEOLOGICAL SURVEY 



CECIL COUNTY 



MARYLAND 
GEOLOGICAL SURVEY 




CECIL COUNTY 



BALTIMORE 

THE JOHNS HOPKINS PRESS 

1902 



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H^M^PfA0Hl^| 



Zt>t frie&enwafb Company 

BALTIMORE, MD., U. S. A. 



APR 10 1903 
D. of D, 



COMMISSION 
JOHN WALTER SMITH, . . . . . p RESIDENT . 

GOVERNOR OF MARYLAND. 

JOSHUA W. HERING, 

COMPTROLLER OF MARTLAND. 

IRA REMSEN", Executive Offices. 

PRESIDENT OF THE JOHNS HOPKINS UNIVERSITY. 

R.W.SILVESTER, Secretaky. 

PRESIDENT OF THE MARYLAND AGRICULTURAL COLLEGE. 



SCIENTIFIC STAFF 

Wm. Bullock Clark, ..... State Geologist. 
SUPERINTENDENT OF THE SURVEY. 



Edward B. Mathews, . . Assistant State Geologist. 

George B. Shattuck, Chief of Division of Coastal Plain Geology. 
L. A. Bauer, . Chief of Division of Terrestrial Magnetism. 
Arthur Bibbins, .... Assistant Geologist. 

Benj. L. Miller, .... Assistant Geologist. 

Frederick B. Wright, .... Assistant Geologist. 



Also with the cooperation of several members of the scientific 
bureaus of the National Government. 



J 



LETTER OF TRANSMITTAL 

To His Excellency John Walter Smith, 

Governor of Maryland and President of the Geological Survey 
Commission. 

Sir: — I have the honor to present herewith a report on The 
Physical Features of Cecil County. This volume is the second of 
a series of reports on county resources, and is accompanied by large 
scale topographical, geological and soil maps. The information con- 
tained in this volume will prove of both economic and educational 
value to the citizens of the county as well as to those who are con- 
sidering residence therein. The report calls attention to many eco- 
nomic deposits not yet utilized. I am, 

Very respectfully, 

Wm. Bullock Clark, 

State Geologist. 
Johns Hopkins University, 

Baltimore, June, 1902. 



CONTENTS 



PAGE 

PREFACE 19 

INTRODUCTION 25 

DEVELOPMENT OF KNOWLEDGE CONCERNING THE PHYSICAL 
FEATURES OF CECIL COUNTY, WITH BIBLIOGRAPHY. By 

George Burbank Shattuck 31 

Introductory 31 

Historical Review 31 

The History of Geographic Research 32 

The History of Geologic Research 36 

The Crystalline Rocks of the Piedmont Plateau 39 

The Potomac Group 41 

The Upper Cretaceous Formations 44 

The Tertiary Formations 45 

The Columbia Group 46 

Bibliography 49 

THE PHYSIOGRAPHY OF CECIL COUNTY. By George Burbank 

Shattuck 63 

Introductory 63 

Topographic Description 64 

The Atlantic Coastal Plain Region 64 

The Topography of the Atlantic Coastal Plain Region 64 

The Drainage of the Atlantic Coastal Plain Region : 66 

The Structure of the Atlantic Coastal Plain Region 68 

The Piedmont Plateau Region 69 

The Topography of the Piedmont Plateau Region 69 

The Drainage of the Piedmont Plateau Region 70 

The Structure of the Piedmont Plateau Region 71 

Topographic History 71 

The Crystalline Rock Forming Stage 71 

The Schooley Peneplain Stage 72 

The Lafayette Stage 73 

The Sunderland Stage 74 

The Wicomico Stage 75 

The Talbot Stage 76 

The Recent Stage 78 

The Origin of the Streams of the Piedmont Plateau 78 



1 2 CONTENTS 

PAGE 

THE GEOLOGY OF THE CRYSTALLINE ROCKS OF CECIL COUNTY. 

Br F. Bascom 83 

Introductory 83 

Geographic and Geologic Relations 84 

Areal Distribution and Character of the Crystalline Formations 87 

Mica-Gneiss 88 

Igneous Intrusives 90 

The Granite-Gneiss 90 

Gabbro and Meta-Gabbro 92 

Meta-Pyroxenites and Meta-Peridotites 93 

Dike Rocks and other Intrusives in the Granite-Gneiss 97 

Intrusives in the Gabbro Belt 100 

Diabase Dikes 100 

Pegmatite Veins 101 

Structural Relations and Age of the Crystalline Formations 103 

The Mica-Gneiss 103 

The Eruptive Rocks 108 

Petrography of the Crystalline Formations 113 

Mica-Gneiss 113 

Granite-Gneiss 117 

Biotite-Granite (Quartz-Monzonite) 117 

Hornblende-Biotite-Granite (Quartz-Monzonite) 119 

Gabbro 121 

Meta-Gabbro or Quartz-Hornblende Gabbro and Hornblende 

Gabbro 121 

Norite and Hypersthene-Gabbro 125 

The Southern Gabbro Belt 128 

Non-Feldspathic Rocks 132 

Pyroxenite 132 

Peridotite 133 

Serpentine 134 

Dike Rocks 135 

Meta-Rhyolite 136 

Micro-Granitic Dikes 139 

Meta-Gabbro 140 

Diabase 140 

Summary 14; - 

Glossary of Geological Terms 143 

THE GEOLOGY OF THE COASTAL PLAIN FORMATIONS. By George 

Burbank Shattuck 149 

Introductory 149 

The Potomac Group 151 

The Patuxent Formation 151 

The Patapsco Formation 153 

The Raritan Formation 155 

The Upper Cretaceous Formations 157 

The Matawan Formation 158 

The Monmouth Formation 159 



MARYLAND GEOLOGICAL SURVEY 13 

PAGE 

The Eocene. 164 

The Aquia Formation 164 

The Neocene 165 

The Lafayette Formation 165 

The Pleistocene 169 

The Columbia Group 169 

The Sunderland Formation 170 

The Wicomico Formation 171 

The Talbot Formation 172 

Interpretation of the Geological Record 173 

Sedimentary Record of the Crystalline Rocks 173 

Sedimentary Record of the Potomac Group 174 

Sedimentary Record of the Upper Cretaceous 176 

Sedimentary Record of the Aquia Formation 177 

Sedimentary Record of the Lafayette Formation 178 

Sedimentary Record of the Columbia Group 179 

THE MINERAL RESOURCES OF CECIL COUNTY. By Edward Ben- 
nett Mathews 195 

Introductory 195 

Building-Stone 196 

Port Deposit 196 

Frenchtown 203 

Clay 204 

Brick and Terra Cotta Clays 206 

Stoneware Clays 207 

Fire-Clays 210 

Kaolin 211 

Flint and Feldspar 217 

Iron Ore 218 

Chrome 221 

Gold 222 

Road Materials 223 

Gabbro 224 

Granite 225 

Gravel 225 

Oil 225 

List of Operators in Mineral Products in Cecil County 226 

THE SOILS OF CECIL COUNTY. By Clarence W. Dorsey and Jay 

A. Bonsteel 227 

Introductory 227 

Agricultural Conditions 227 

Soil Formations 229 

Cecil Loam 230 

Cecil Clay 233 

Cecil Mica-Loam 235 

Conowingo Barrens 236 

Conowingo Clay 238 



14 CONTENTS 

PAGE 

Sassafras Loam 239 

Norfolk Sand 241 

Susquehanna Gravel 243 

Elkton Clay 245 

Susquehanna Clay 246 

THE CLIMATE OF CECIL COUNTY. By Oliver L. Fassig 249 

Introductory 249 

Temperature Conditions 250 

Normal Temperatures and Departures therefrom 252 

Extremes of Temperature 254 

Rainfall 257 

Snowfall 260 

THE HYDROGRAPHY OF CECIL COUNTY. By H. A. Pressy 263 

Octoraro Creek 266 

Susquehanna River 272 

THE MAGNETIC DECLINATION IN CECIL COUNTY. By L. A. 

Bauer 289 

Meridian Line 290 

THE FORESTS OF CECIL COUNTY. By H. M. Curran, with an Intro- 
duction, ry George B. Sudworth 295 

Introduction 295 

Location 296 

Topography and Soil 297 

Drainage 297 

Woodlands and Forests 298 

Forest Types 298 

Barrens Timber 298 

Shore Timber 300 

Forest Trees 302 

Conifers 302 

Hardwoods 303 

Distrirution 304 

Important Commercial Trees 304 

Inferior Commercial Trees 305 

Use of Material 305 

Building Material 306 

Pulpwood 306 

Ties and Telegraph Poles 307 

Fencing 307 

Charcoal and Cordwood 308 

Forest Fires 308 

Fire Protection 309 

Future of Forests 310 

Early Condition 310 

Producing Capacity 311 

Improvement 312 

In hex 



31.". 



ILLUSTRATIONS 



'E FACING PAGE 

I. View from Wildcat Point, showing Gorge and Islands of the 

Susquehanna River 25 

II. Views of Cecil County 32 

Fig. 1. — View Susquehanna River from below Port Deposit. . . 32 

Fig. 2. — Gilpin Rocks, near Bay View 32 

III. View looking northeast from Grays Hill, near Elkton 40 

IV. Map showing Physiographic Divisions of Cecil County 64 

V. Views of Cecil County 68 

Fig. 1. — Topography of Elk Neck, Cecil County 68 

Fig. 2. — Turkey Point, from Maulden Mountain 68 

VI. Views of Cecil County 72 

Fig. 1. — A young valley in unconsolidated Coastal Plain 

Deposits 72 

Fig. 2. — Wave-cut cliff on west shore of Elk Neck 72 

VII. Views of Cecil County 80 

Fig. 1. — Susquehanna from Wildcat Point, showing side 

valleys 80 

Fig. 2. — View of rocky side-stream near Bald Friar 80 

VIII. Views of Piedmont Plateau 88 

Fig. 1. — Wildcat Point, showing depth of gorge cut in Pied- 
mont Plateau by Susquehanna River 88 

Fig. 2. — Level Surface of Piedmont Plateau away from main 

drainage lines 88 

IX. Views of Piedmont Plateau 96 

Fig. 1. — View showing barrens underlain by serpentine 96 

Fig. 2. — View showing farmlands underlain by granite- 
gneiss 96 

X. Views of Piedmont Plateau structure 104 

Fig. 1. — Eailroad cut in contorted gneiss, above Bald Friar. . 104 

Fig. 2. — Nearer view showing character of folding 104 

XI. Views of Piedmont Plateau 136 

Fig. 1. — Gilpin Rocks (metarhyolite), near Bay View 136 

Fig. 2. — Falls over Gilpin Rocks, near Bay View 136 

XII. Geological sections in Cecil County 152 

Fig. 1. — Patapsco and overlying Raritan formations, Lower 

White Banks 152 

Fig. 2. — Nearer view of Raritan formation, Maulden Moun- 
tain 152 

XIII. Geological sections in Cecil County 156 

Fig. 1. — Raritan formation overlain by Matawan 156 

Fig. 2. — Raritan formation overlain by Pleistocene, Northeast 

River 156 



16 

PLATE 

XIV. 



XV. 



XVI. 



XVII. 



XVIII. 
XIX. 



XX. 



XXI. 



XXII. 



XXIII. 



XXIV. 

XXV. 

XXVI. 



XXVII. 



XXVIII. 



XXIX. 



ILLUSTRATIONS 

FACING PAGE 

Geological sections in Cecil County 160 

Fig. 1. — Cliff showing Matawan Monmouth contact, Sassa- 
fras River : 160 

Fig. 2. — Bluff showing Eocene, at Georgetown 160 

Geological sections in Cecil County 168 

Fig. 1. — View showing Sunderland terraces with Lafayette 
in the foreground 168 

Fig. 2. — Top of the Wicomico formation at Turkey Point.. 168 
Geological sections in Cecil County 176 

Fig. 1. — Fossil tree stump in Talbot formation, Bohemia 
River 176 

Fig. 2. — Section in Talbot formation, near Perry ville 176 

.Mineral Resources of Cecil Count y 196 

Fig. 1. — View showing location of McClenahan granite quarry, 
Port Deposit 196 

Fig. 2. — Kaolin-washing plant, Maryland Clay Company, 

Northeast 196 

Map of central Cecil County 204 

Mineral Resources of Cecil County 216 

Fig. 1. — Outcrop of kaolin in Sutton cut, near Perry ville 216 

Fig. 2. — Flint mill and kiln, Conowingo 216 

Agricultural views in Cecil County 228 

Fig. 1. — Weathering of granite into Cecil loam, near French- 
town 228 

Fig. 2. — Crystalline rocks overlain by gravel 228 

Agricultural views in Cecil County 232 

Fig. 1. — Characteristic topography in Susquehanna gravel 
area 232 

Fig. 2. — Typical farm in central Cecil County 232 

Agricultural views in Cecil County 240 

Fig. 1. — Farm-lands, Elk Neck 240 

Fig. 2. — Farm-lands, Sassafras Neck 240 

Hydrography of Cecil County 264 

Fig. 1. — Bohemia river, with thin fringe of shore-timber 264 

Fig. 2. — Little Elk Creek with river birch and sycamore 264 

Charcoal-burners' camp 295 

Map of Cecil County showing wooded areas 296 

Barrens timber 298 

Fig. 1.— A thin stand, due to fire 298 

Fig. 2. — An area recently cut 298 

Shore timber 300 

Fig. 1. — A good stand, Sassafras Neck 300 

Fig. 2. — Interior view of above 300 

Shore timber 304 

Fig. 1. — A defective old Chestnut in young growth 304 

Fig. 2. — Tulip-tree coppice. A dense stand 304 

Roadside trees 310 

Fig. 1. — Black Cherry, Red Cedar and Sassafras 310 

Fig. 2. — Scrub Pine on land once cultivated 310 



MARYLAND GEOLOGICAL SURVEY 17 

PLATE FACING PAGE 

XXX. Cordwood for Charcoal 312 

Fig. 1.— Making a kiln 312 

Fig. 2.— Burning a kiln 312 

FIGURE PAGE 

1. Showing position of Sunderland shore-line 74 

2. Showing position of Wicomico shore-line 76 

3. Showing position of Talbot shore-line 77 

4. Diagram showing origin of superimposed river 81 

5. Diagram showing type of unsymmetrical overturned folding 103 

6. Section showing conformable contact of limestone with overlying 

mica-gneiss 105 

7. Generalized section from Merion to Haverf ord, Pa 107 

8. Diagram showing pre-Talbot valley 187 

9. Diagram showing advancing Talbot shore-line and ponded stream... 188 

10. Diagram showing later stage in advance of Talbot shore-line 189 

11. Ideal section showing advance of Talbot shore-line 190 

12. Highest, normal, and lowest monthly mean temperatures at Wood- 

lawn, Cecil County 251 

13. Absolute, Maximum, Average Maximum, Average Minimum and Ab- 

solute Minimum Temperatures at Woodlawn, Cecil County 252 

14. Maximum, Average and Minimum Monthly precipitation, Woodlawn, 

Cecil County \ 258 

15. Discharge of Octoraro Creek at Rowlandsville during 1897 269 

16. Discharge of Octoraro Creek at Rowlandsville during 189S 270 

17. Discharge of Octoraro Creek at Rowlandsville during 1899 270 

18. Profile of Susquehanna river from its source to Williamsport, Pa. . . . 274 

19. Profile of Susquehanna river from Williamsport, Pa., to Havre de 

Grace 274 

20. Discharge of the Susquehanna river at Harrisburg, Pa., during 1891- 

1898 284 

21. Discharge of the Susquehanna river at Harrisburg, Pa. during 1899.. 285 

22. Discharge of the Susquehanna river at Harrisburg, Pa. during 1900 . . 285 

23. Cordwood for pulp, Elkton 306 

24. Cordwood for domestic use, Elk Neck 308 



PREFACE 

The present volume on Cecil county forms the second in a series 
of reports dealing with the physical features of the several counties 
of Maryland. In it are full descriptions of the geology and mineral 
resources, the surface configuration, agricultural, climatic, hydro- 
graphic, magnetic, and forestry conditions of Cecil county. The 
more systematic treatment of the geology and paleontology of the 
area will be presented in other publications. 

The Introduction contains a brief statement regarding the location, 
boundaries, and history of Cecil county, and a summary of its chief 
physical characteristics. 

The Development of Knowledge Concerning the Physical Features 
of Cecil County with Bibliography, as sketched by George Burbank 
Shattuck, gives a concise statement regarding the history of geo- 
graphic and geologic research on the physical features of the county, 
while the bibliography gives a list of more important papers in which 
this knowledge has been set forth. 

The Physiography of Cecil County, by George Burbank Shattuck, 
embraces not only a description of the surface features characteristic 
of the region and their distribution, but includes a clear statement of 
the manner in which these features have been produced and of the 
processes by which this has been accomplished. 

The Geology of Cecil County, by F. Bascom and George Bur- 
bank Shattuck, is described in two well-defined chapters, determined 
by the geological deposits of the county. The Geology of the Crystal- 
line Rocks, by Dr. Bascom, dealing with the older and more intricate 
rocks of the Piedmont Plateau, was conducted under the auspices of 
the U. S. Geological Survey. In this paper is a careful description of 
the character, structure, and areal distribution of the metamorphic 
and igneous rocks which form part of the complex series of crystalline 
rocks found along the eastern flanks of the Appalachian Mountains 



20 PREFACE 

throughout their entire extent. This more general chapter is fol- 
lowed by one in which are given the detailed chemical and micro- 
scopical examinations on which the broader generalizations are based. 
The Geology of the Coastal Plain Formations by Dr. Shattuck, 
includes a discussion of the different geological formations found 
within the southern portion of Cecil county, with a description of 
the salient features of the different formations composing this exten- 
sive series of gravels, sands, and clays. The chapter dealing with the 
interpretation of the geological record as shown in the deposits of 
the entire county deserves especial attention, as in it is given an 
interesting history of the numerous changes which this area has 
undergone. 

The Mineral Resources of Cecil County, by Edward B. Mathews, 
deals with the mineral wealth of Cecil county. The chief industries 
center around the building stone and clay. Occasionally there is 
some activity in the quarrying of flint, feldspar and iron ore. In the 
past Cecil county was a prominent producer of iron and chrome. 
The reports on the clays and building stone are based on the much 
fuller discussions of these industries already published by the Survey. 

The Soils of Cecil County, by Clarence W. Dorsey and Jay A. 
Bonsteel, contains a discussion of the leading soil types showing their 
character and distribution and the crops best suited to each. This 
investigation was conducted under the supervision of Milton Whitney, 
Director of the Division of Soils, U. S. Department of Agriculture, 
who detailed Mr. Dorsey and Dr. Bonsteel to carry on this work in 
cooperation with the Maryland Geological Survey. 

The Climate of Cecil County, by Oliver L. Fassig, gives a sum- 
mary of the climatic conditions in the county, and shows what may 
reasonably be expected concerning the variations in temperature and 
rainfall during the different months of the year. These conclusions 
are the result of a careful digest of all the observations recorded at 
intervals from 1843 down to the present time. 

The Hydrography of Cecil County, by H. A. Pressey, of the 
Hydrographic Division of the U. S. Geological Survey, contains a 
complete record of the stream measurements made in Cecil county, 



MARYLAND GEOLOGICAL SURVEY 21 

especially on Octoraro Creek, and gives an account of the monthly 
and daily flow of the Susquehanna, as measured at Harrisburg, Penn- 
sylvania, since 1890. 

The Magnetic Declination in Cecil County, by L. A. Bauer, Chief 
of the Division of Terrestrial Magnetism of the II. S. Coast and 
Geodetic Survey, contains much important information for the local 
surveyors who are required to re-run old property lines laid out by 
compass. Dr. Bauer has been engaged for several years in a study of 
the magnetic conditions in Maryland. 

The Forests of Cecil County, by H. M. Curran, with an introduc- 
tion by Geo. B. Sudworth, is a valuable and suggestive contribution 
to the forestry interests of Cecil county. In this report Mr. Curran 
brings out many items of interest regarding the timber of the county, 
the depleted condition of the forests and the manner in which these 
may be improved. This work has been conducted by the Forestry 
Division of the U. S. Department of Agriculture in cooperation with 
the Maryland Geological Survey, as indicated in Mr. Sudworth's 
introduction. 

The State Geological Survey desires to extend its thanks to the 
several National organizations which have liberally aided it in the 
preparation of many of the papers contained in this volume. The 
Director of the IT. S. Geological Survey, the Superintendent of the 
IT. S. Coast and Geodetic Survey, the Chief of the IT. S. Weather 
Bureau, and the Chiefs of the Soil and Forestry Surveys of the 
Department of Agriculture have granted every facility in the conduct 
of the several investigations. The value of the report has been much 
enhanced thereby. 

The illustrations contained in the volume have been obtained from 
various sources. Many of the photographs were taken by the authors 
of the several papers while in the field. Several of the views were 
taken by Dr. Edward B. Mathews and Messrs. A. Bibbins and A. 
Johannsen. 



THE 



PHYSICAL FEATURES 



OF 



CECIL COUNTY 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE I. 




< 

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THE PHYSICAL FEATURES OF CECIL COUNTY 



INTRODUCTION. 



Cecil county, the northeastern county of Maryland, is located be- 
tween the parallels 39° 22^' and 39° 43' 26" north latitude and the 
meridians 75° 46' and 76° 14' west longitude. The territory within 
these limits includes both land and water areas, the former embracing 
about 375 square miles, or nearly a quarter of a million acres. The 
county is bounded on the north by the Mason and Dixon Line, which 
separates it from Lancaster and Chester counties, Pennsylvania; on 
the east by a line, relocated by Mason and Dixon, which runs between 
it and Newcastle county, Delaware. This eastern boundary line is 
composed of three parts. The southern portion is the northern end 
of the line running from the " middle point " of the peninsula of the 
Eastern Shore of Maryland and Delaware tangent to a circle of twelve 
miles radius whose center is at Newcastle, Delaware. This portion of 
the boundary extends from the Sassafras river to the " tangent point " 
which lies just east of the race-course at Iron Hill. The second and 
central division of the eastern boundary is a segment of the " twelve- 
mile circle " lying between the "tangent point " and the " point of 
intersection " where a due north line from the " tangent point " cuts 
the northeasterly trending segment of the circle. The point where 
these two line intersect is marked by a stone standing a short distance 
south of the tracks of the Baltimore and Ohio Railroad. The third 
and northern portion of the eastern boundary is that part of the 
above mentioned north line which extends from the " point of inter- 
section " to the northeastern corner of the county and state. The 
county is bounded on the south by the channel of the Sassafras river, 
and on the west by the channels of Chesapeake Bay and of the Sus- 



26 INTRODUCTION 

quehanna river. The latter line makes Garrett Island part of Cecil 
county, but excludes Spencer, Roberts, and Amos Islands. 

Cecil county as an independent division of the State was first recog- 
nized on June 6, 1674, by the proclamation of Governor Charles 
Calvert. The limits of the county at first included all that portion 
previously constituting part of Baltimore county, which lay between 
the Susquehanna on the west, the Chester river on the south, and the 
limits of Maryland on the east and north, which were then held to be 
at Delaware river and the 40th parallel, respectively. A second 
proclamation, issued a few days later (June 19th), revoked so much 
of the first proclamation as affected the lands previously regarded as 
part of Kent county. This separation of Cecil and Kent counties 
was reiterated in the Acts of Assembly for 1695, and yet terms of 
separation were not clearly set forth until in the Acts of 1706, Chap. 
3, Sect, 1, when it is definitely stated that " Cecil county shall con- 
tain all the land on the north side of Sassafras river and Kent county, 
and shall be bounded on the east and north with the exterior bounds 
of this province, and on the west with Susquehanna river and Chesa- 
peake *Bay, and on the south with Sassafras river and Kent county," 

The region now embraced by Cecil county was explored, and trad- 
ing stations were probably established before the settlement was 
made by Lord Baltimore's party at St. Mary's. As early as 1608, 
Captain John Smith explored the region and mapped its shore line. 
The earliest mention of Cecil county as sneli occurs, according to 
Johnston, 3 in Augustm lien-man's journal, which refers to the record- 
ing on l.".th September, 1659, of a survey and of Lord Baltimore's per- 
mit to have the town and county which he proposed to erect called 
( lecilton and Cecil county. The former was never built, but left its 
record in the name Town Point. During the seventeenth century the 
inhabitants of the county were often harassed by the Indians, and 
during the early part of the eighteenth much time was lost iu border 
tends, yet in spite of these distractions Cecil county very early in 
ii- history became one of the wealthiest and most progressive coun- 
ties of the State. To-day it is the home of prosperous, enterprising 
agriculturists, descendants in very many cases of the original settlers. 

'Geo. Johnston, History of Cecil county, Maryland, Elkton, issi, 54s pp. 



MARYLAND GEOLOGICAL SURVEY 27 

Situated at the head of the Bay, on the main line of travel between 
the cities of the Atlantic coast, Cecil county has been well provided 
with transportation facilities. Across the center of its territory, from 
the Susquehanna on the west to the Delaware line on the east, run 
the Baltimore and Ohio and the Philadelphia, Wilmington and 
Baltimore railroads, while the northern portion of the county is 
served by branches of the Pennsylvania system running up the Sus- 
quehanna with an intersecting line extending from Octoraro Junction 
eastward through Rising Sun into Chester county, Pennsylvania. 
The southern half of the county has no railway facilities, but is so dis- 
sected by the estuaries of the bay that few points are more than five 
miles distant from water transportation. 

The surface configuration of the county is attractive, the view being- 
diversified by sheets or streams of water, terraces rising gently from 
the level of the Bay, isolated hills and the higher uplands carved in 
pleasing contours by the winding courses of the streams. According 
to the character of .the surface the county is separable into two main 
divisions, the Piedmont Plateau on the north and the Coastal Plain 
on the south. As has been pointed out in another place, the Coastal 
Plain is again divisible into a Western Shore, characterized by rolling 
country, and an Eastern Shore division, whose surface is extremely 
flat and featureless. 

Cecil county contains neither mountains nor hills of importance. 
The highest points run but little over 500 feet above the level of the 
sea and do not stand conspicuously above the general rolling surface 
of the country in which they are situated. Id the Piedmont Plateau, 
the three most conspicuous elevations are Foys Hill, with an altitude 
of 420 feet; Woodlawn, 456 feet, and the vicinity of Rock Springs, 
540 feet. In the Coastal Plain, a range of low hills extends down 
the center of Elk Neck. These are known, beginning at the north, 
as the Hog Hills, which reach an elevation of about 300 feet; Black 
Hill, 311; Elk Neck, 260; Bull Mountain, 306, and Maulden Moun- 
tain, 220. Near the Delaware state line, where the Coastal Plain 
approaches the Piedmont Plateau, Grays Hill rises abruptly from the 
surrounding level to a height of 268 feet above the sea. 



28 INTRODUCTION 

Cecil county, as a whole, drains toward Chesapeake Bay. The 
streams in the western part of the Piedmont, the most important of 
which are the Conowingo and Octoraro creeks, flow into the Susque- 
hanna river, while the other streams of the Piedmont flow south and 
enter the head of Chesapeake Bay; of these the most important are 
Principio, Big and Little Elk and Northeast creeks. The streams 
of the Coastal Plain have been depressed since their valleys were 
excavated and converted into estuaries. These estuaries prolong the 
navigable waterways beyond the limits of Chesapeake Bay well into 
the interior of the county; the most important of these are Northeast, 
Elk and Sassafras rivers and Back and Bohemia creeks. 

Cecil county lies in two great geologic provinces, the Piedmont 
Plateau and the Coastal Plain. The rocks of the Piedmont Plateau 
are both eruptive and metamorphic, and antedate, by a great per- 
iod, the deposits belonging to the Coastal Plain province; indeed, 
the rocks of the Piedmont Plateau have experienced so much dis- 
turbance that their structure and geologic history are now extremely 
complicated and very difficult to unravel. The reverse is true of the 
formations belonging to the Coastal Plain province; none of the 
deposits here date back earlier than the Jurassic and perhaps not 
before the Lower Cretaceous. Except for local indurations they are 
unconsolidated. The earlier deposits of the Coastal Plain series are 
tilted slightly toward the southeast but the younger ones, although 
they have been somewhat elevated since their deposition, have not 
apparently suffered much, if any, differential uplift and are as hori- 
zontal as when first deposited. 

The mineral resources are varied, including building stone, clays 
for brick, terra cotta, and stoneware, fire-clay, kaolin, flint, chrome, 
iron and possibly gold. Each of these has influenced the develop- 
ment of the wealth of the county. 

The agricultural conditions, closely related to the underlying 
geological formations, show a corresponding diversity; wheat, corn, 
timothy, and clover are the main crops, and these are grown over the 
entire county. Truck is grown to some extent in the southern portion 
of the county, but in the northern and central parts the growing of 



MARYLAND GEOLOGICAL SURVEY 29 

late crops of tomatoes and corn for canning purposes has for a long 
time been an important industry and lias placed Cecil county in the 
first rank among the tomato-canning districts of the country. 

The climate of the county is good. The normal temperature lies 
between that of Baltimore and Philadelphia with an average daily 
range of 14-21°, which in extreme cases seldom exceeds 40°. The 
precipitation is evenly distributed, the monthly fall varying from 
three inches in January and February to six inches in August. A 
period of more than four or five weeks without rainfall is extremely 
improbable. 

Detailed information regarding the physiography, geology, mineral 
resources, soils, hydrography, climate, terrestrial magnetism, and 
forestry are given in the succeeding chapters. 

E. B. M. 



DEVELOPMENT OF KNOWLEDGE CONCERN 

ING THE PHYSICAL FEATURES OF CECIL 

COUNTY WITH BIBLIOGRAPHY 

BY 

GEORGE BURBANK SHATTUCK 



Introductory. 

The observations made by the early explorers who visited Cecil 
county relate to subjects which have since grown to be distinct fields 
of investigation. Those relating to the geography and geology have 
been gleaned from various papers by the author and an attempt 
has been made to group them under their respective heads. The 
narrative of geographic research begins with an account of the 
exploration by Captain John Smith in 1608 and ends with the latest 
work of the State Geological Survey made during the summer of 
1900. The history of geologic research begins with Wm. Maclure's 
investigations of 1809 and is brought down to 1901 when the most 
recent paper was published. As geological research has progressed, 
it has been found necessary to subdivide more and more the various 
crystalline rocks and unconsolidated deposits found within the county. 
In order to render this advance in knowledge more intelligible, the 
various observations made by former explorers have been so grouped 
as to throw light on the evolution of the present geological 
classification. 

Historical Review. 

Cecil county, lying as it does at the head of Chesapeake Bay and 
penetrated by numerous navigable estuaries, is most favorably situ- 
ated for colonization, and it is not surprising that it was early explored 
and settled by Europeans. In this, as with every other new region, 
the exploration? were at first incomplete and the resulting maps erro- 



32 THE PHYSICAL FEATURES OF CECIL COUNTY 

neous, but as civilization advanced and the wealth of the community 
increased, the rough outline maps were gradually revised and super- 
ceded by more exact and satisfactory ones. The history of explora- 
tion in Cecil county is therefore a record of the gradual accumulation 
of information which was at first vague and general and has only of 
late become definite and special. This history will be discussed under 
the two divisions of geographical research and geological research. 

THE HISTORY OF GEOGRAPHIC RESEARCH. 

The first geographical exploration 1 which was made into the region 
which is now known as Cecil county was carried on in the summer of 
1608 by Captain John Smith and a few companions, although the 
results were not published until 1612-14. The motive which prompted 
Smith to this enterprise was the exploration of Chesapeake Bay and 
the adjacent county, so that the examination of Cecil county was only 
a portion of the work accomplished. His description of the country 
about the head of the Bay is as follows: 

" From the head of the Bay to the Northwest, the land is moun- 
tainous, and so in a manner from thence by a Southwest line ; so that 
the more Southward, the farther off from the Bay are those moun- 
taines. From which fall certaine brookes which after come to the 
fine principall navigable rivers. These run from the Northwest into 
the Southeast, and so into the West side of the Bay, where the fall 
of every River within 20 or 15 miles one of another." 

In all, Smith spent scarcely a month in his exploration of Chesa- 
peake Bay, but nevertheless was able to present a remarkably well- 
proportioned map, considering the difficulties which he encountered 
and the rough methods of work he employed. This map was used 
for some time afterwards as a basis of exploration and settlement. 

In 1651, the Farrer map of the environs of Chesapeake Bay and 

the surrounding country appeared. This map, which was drawn by 

, A T irginia Farrer, was distorted so as to prove that " in ten dayes 

1 For illustrations of these early maps and the conditions under which they were 
made, see Mathews, Maps and Mapmakers of Maryland, Md. Geol. Survey, volume 
II, 1898, pp. :;:'.7-488. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, FLATE II. 




Fig. 1.— VIEW OF SUSQUEHANNA RIVER FROM BELOW PORT DEPOSIT. 




FlG. 2.-GILPIN ROCKS. NEAR RAY YIEW. 



VIEWS OF CECIL COUNTY, 



MARYLAND GEOLOGICAL SURVEY 33 

march with 50 foote and 30 horsemen from the head of Ieames River, 
ouer those hills and through the rich adiacent Yallyes beautified with 
profitable rivers which necessarily must run into yt peacefull Indian 
Sea " one might arrive in New Albion or California. In this map, 
the region now occupied by Cecil county was so distorted that the 
map was practically useless. 

Fifteen years later, in 1666, George Alsop published a map which 
embraced the environs of Chesapeake Bay from a point in Yirginia 
a little south of the Potomac river northward to what is now in part 
Delaware and Pennsylvania. The map was issued in a small pamph- 
let and was based on personal exploration throughout the region 
represented. Although many of the details which were placed on 
the map had been obtained by personal exploration, still Alsop was 
doubtless familiar with the early Smith map and was guided not a 
little by it. The map is on a larger scale and shows more detail than 
represented by Smith, yet it cannot be said to add much to the real 
knowledge of the region, because of its diagrammatic character and 
extremely distorted proportions. It is just such a map as a rover or 
an untrained hunter, who had explored the region in a general way. 
might produce. The Susquehanna river, here spelled Susquelian- 
nock, is represented, also the " Elke " and " Sasafrax " rivers, as well 
as another stream, not named, but which, from its position, is prob- 
ably either Back or Bohemia Creek. The rolling country within 
Cecil county is expressed by clusters of hills. Scattered about the 
surface of Cecil county and the neighboring region are sketches 
showing a male and a female indian, the former in the act of dis- 
charging a flintlock musket; also a hog, a dog and a fox. These 
illustrations were drawn to accompany the description and were prob- 
ably placed on the face of the map to economize space. 

The map which Smith published in 1612 (?) was not excelled by 
other explorers until 1670, when Augustin Herrman brought out a 
map of the region extending from southern New Jersey to southern 
Yirginia. Herrman, it seems, offered to make a map of Lord Balti- 
more's territory provided Lord Baltimore in return would grant him a 
manor along Bohemia River; this proposition Lord Baltimore accepted 
3 



34 THE PHYSICAL FEATURES OF CECIL COUNTY 

in 1660 and Herrmau soon after began to fulfil his part of the contract. 
He was engaged in this work for about ten years, and the map which 
he finally produced indicates that he had considerable talent, not only 
as a surveyor but also as a draughtsman. This map was published in 
1670 and embraced the territory from the southern half of New 
Jersey to southern Virginia and westward to the limit of tide-water. 
The configuration of the shore about the head of Chesapeake Bay is 
fairly well represented. The principal estuaries, including the Sus- 
quehanna, Northeast, Elk and Sassafras rivers are shown and their 
relative proportions well represented. " Ocktoraaro " (Octoraro), 
" Canoonawengh " (Conowingo) creeks and Northeast River also find 
a place in the map. Numerals are placed in the waterways to 
indicate the relative depths of the streams. A number of settlements 
are indicated and the map, as a whole, shows that Herrman had repre- 
sented with considerable ability a large amount of information which 
he had been instrumental in gathering. 

The account of the development of the geography of Cecil county 
will not be complete without a notice of the excellent work done by 
Charles Mason and Jeremiah Dixon in running the historic Mason 
and Dixon Line. Their commission was dated the 9th of December, 
1703, and their work was completed a little less than five years later, 
on the 9th of November, 1768. No map appears to hftve been pub- 
lished as a result of these works, though one was prepared ' in manu- 
script and many notes of interest were recorded in their field books. 
When Col. Graham, equipped with refined instruments and assisted 
by a full corps of engineers, made his survey in 1849-50, his work did 
not show a deviation of two inches on either side of the center of the 
post erected by Mason and Dixon at the termination of the line run- 
ning due north, thus proving the extreme accuracy of the original 
work. 

At about the time of the outbreak of the Revolutionary War, 
Anthony Smith published a chart of Chesapeake Bay on a scale of ■ , >\ 
miles to the inch. This chart was intended for a guide to navigators, 
and such information as shoals, channels, islands and the various 
depths of water were represented. 

1 Manuscript Copies still exist and these have been reproduced. 



MABYLAOTD GEOLOGICAL SURVEY 35 

Another chart was published by Hauducoeur in 1709, which em- 
braced the region about Havre de Grace and the head of the Bay. 
The chart is beautifully executed and the topography of each side 
of the Susquehanna river is expressed in hachure. The map extends 
from Spesutia Narrows to a point about five miles beyond the Mason 
and Dixon Line. On each side of the river throughout this district, 
the position of roads, streams, houses, property boundaries and the 
condition of cultivation, is indicated; even names are attached to cer- 
tain of the roads and farms. An attempt is also made to depict the 
character of the bottom which underlies the mouth of the Susque- 
hanna and the region about the head of the Bay. 

In 1791, Dennis Griffith assembled all available information and 
published a map of the entire State which was not excelled until 
Alexander began the publication of his maps in the fourth decade 
of the last century. In Griffith's map the outline of the coast around 
the head of Chesapeake Bay is platted in about the form which we 
know it today. The principal streams of Cecil county and a large 
number of towns are also represented. 

A marked advance in the cartography of this region occurred in 
1839, when Prof. J. T. Ducatel, then State Geologist of Maryland, 
published his geological report of Cecil county. This report was 
accompanied by a map of the region prepared by John H. Alexander. 
This map of Cecil county was the best that had been produced and 
was not excelled until the map which is published by the present 
State Geological Survey. In the Alexander map, the topography 
was expressed by hachure and the map executed on the scale of 
1 :150,000. The coast-line was laid down with greater accuracy than 
in any map published up to that time, and an attempt was made to 
distinguish between the topographic features of the Coastal Plain and 
those of the Piedmont Plateau to the north of it. The elevations, 
however, are represented by sketches of conical hills which give the 
impression of . A T olcanic cones rather than of a generally rolling 
country. 

During the summer of 1845, the IT. S. Coast and Geodetic Survey 
began the survey of the shore-line about the head of Chesapeake 
Bay. The maps, which were subsequently published, attained a 



36 THE PHYSICAL FEATURES OF CECIL COUNTY 

very high grade of workmanship. Besides the position of the shore- 
line, they indicated by means of numerals, the depths of water in 
feet and fathoms, the character of the bottom and the topography of 
the coast for about two miles back from the shore-line. 

In 1858, Simon J. Martenet published a map of Cecil county on 
the scale of 1-J miles to the inch. This is a wall map measuring 41 
by 41 inches. It indicates the position of roads and towns but does 
not represent the relief. 

An atlas of Cecil county was published in 1877 by Lake, Griffing 
and Stevenson. This atlas, besides including a map of the county as 
a whole, contained also plats of the different districts and the most 
important towns. JSTo elevations are indicated on any of these maps 
but the culture, such as common roads, private roads, turnpikes, rail- 
roads and houses, is well represented. 

ISTo other cartographic work of importance appeared until the sum- 
mer of 1000, when the State Geological Survey in cooperation with 
the I". S. Geological Survey published the new topographic sh'eets 
on which were platted portions of Cecil county. These sheets are 
four in number, each one carrying a portion of the county; they are 
published on a scale of 1:62,500, or about one mile to the inch. 
Relief is indicated by 20 foot contours printed in brown, the hydro- 
graphy is printed in blue and the culture, including boundary lines, 
highways, railroads, houses and names is printed in black. These 
sheets with the election districts added have been united and re- 
engraved for the atlas which accompanies this report. 

THE HISTORY OF GEOLOGIC RESEARCH. 

From a very early date, those who have examined the geology of 
Cecil county have distinguished between the crystalline rocks of the 
Piedmont Plateau and the unconsolidated sediments of the Coastal 
Plain. These two provinces have always been considered as distinct 
and as separated from each other by a great time interval. In the 
early days of geologic research in Cecil county, when those who pre- 
tended to study the science at all were either amateurs or were busy 
with other occupations during the greater part of the time, the in- 



MARYLAND GEOLOGICAL SURVEY 37 

trinsic problem of the Piedmont rocks presented difficulties too great 
to be overcome, and attention was consequently directed to unravel- 
ling' the stratigraphy of the Coastal Plain. Of the large number of 
papers which have been published since investigation commenced in 
Cecil county, only a very few are of sufficient importance to deserve 
mention in this review. 

The first paper of importance was published by William Maclure 
in 1809. Although this contribution dealt in a broad way with the 
geology of the United States, yet it shed considerable light on Cecil 
county. Maclure separated the formations of that region into two 
great provinces, the Primitive and the Alluvial. These two divisions 
corresponded to what we now know as the rocks of the Piedmont 
Plateau and the deposits of the Coastal Plain, and the line which 
separated the two groups was drawn by Maclure approximately as it 
is known to-day. This paper, which was accompanied by a geological 
map, was republished many times in subsequent years; the last one 
appearing in 1826. The unity of the Coastal Plain deposits as pro- 
mulgated by Maclure seems to have been quite generally accepted at 
the time, for Hayden, in 1820, in a series of essays which attracted 
considerable attention, referred to these Alluvial deposits and 
advanced the theory that they were deposited not by rivers but were 
swept in by a great flood which crossed North America from north- 
east to southwest. Two years later, Parker Cleaveland endorsed 
Maclure's map by reproducing it in his treatise on mineralogy. 

No serious exception seems to have been made to Maclure's inter- 
pretation until 1824, when Professor John Finch, an Englishman who 
was making a tour of the United States, called attention to the com- 
plex character of the Alluvium. He divided it into Ferruginous sand 
and Plastic clay, and correlated these with the Newer Secondary and 
Tertiary of Europe, Iceland, Egypt and Hindustan. His correlations 
were made largely on lithologic distinctions and on a general like- 
ness of fossil forms without a close or minute comparison of either. 
Of more significance, however, was his statement that future work 
would show some eight or ten formations between the Alleghany 



38 THE PHYSICAL FEATURES OF CECIL COUNTY 

Mountains and the Atlantic Ocean which would agree with later 
s1 rata of Europe. 

John Finch's suggestions seemed to have had a stimulating effect 
on American geologists, for a number of papers followed in rapid 
succession in which the attempt was repeatedly made to divide the 
Alluvium into its natural formations and to correlate them with 
established horizons in Europe. These early investigators, although 
keen men in certain instances, did not, however, have the necessary 
training to cope successfully with the problems which they sought to 
solve. None of them seemed to have realized the peculiar difficulties 
of Coastal Plain stratigraphy. All of them did their work rapidly 
and unsystematically, and most of them reached their conclusions 
prematurely. Seldom was a paper accompanied by a geological map, 
few localities were given and descriptions w T ere usually ambiguous 
and unsatisfactory. The result was that the formations described 
by one investigator were almost sure to be included in those described 
by another, and out of the endless confusion which arose from this 
sort of work, little of value has survived. It was not until geologists 
in connection with the Johns Hopkins University, the United States 
and Maryland Geological Surveys, made a systematic study of Cecil 
county and the adjacent region that a subdivision and a natural classi- 
fication was finally worked out. 

In 1825, Van Rensselaer carried Finch's views still further and 
declared that the deposits of the Atlantic Coast from Martha's Vine- 
yard southward and included between the Alleghany Mountains and 
the ocean were Tertiary. He divided this Tertiary into Plastic clay, 
London clay and Upper Marine. A little later, Morton accepted 
Van Rensselaer's correlation of the great deposits bearing fossil shells 
in Maryland with the Upper Marine of Europe, but appears to have 
expanded its limits somewhat; he also described fossil shells which 
were secured from the beds which we now know belong to the Upper 
Cretaceous. A little later, Vanuxem and Morton divided the Coastal 
Plain deposits into Secondary and Tertiary and ancient and modern 
Alluvial. They defined also the boundaries of each. Two years 
later, in 1830, Morton correlated the Ferruginous sand formation in 



MARYLAND GEOLOGICAL SURVEY 39 

which greensand was found with the Lower Chalk of Europe. In 
1838, Ducatel published a short paper dealing with the geology of 
Cecil county. This contribution was devoted largely to pointing out 
localities of various minerals and rocks, and as the subject was ap- 
proached from an economic side little, if anything, was added to the 
geological knowledge of the region. In 1841, Booth wrote a memoir 
on the geology of Delaware, in which he subdivided the formations 
of that state into Primary, Upper Secondary, Tertiary and Recent. 
As many of the formations in Cecil county run directly over into 
Delaware, Booth's classification would apply in great measure to 
Cecil county as well. The Primary formation included the Crystal- 
line rocks; the Upper Secondary, Tertiary and Recent formations 
were confined to the Coastal plain. In 1853, Marcou brought out his 
monograph on the " Geology of North America." In this volume 
he published two maps, one of which represented the Piedmont of 
Cecil county as composed of Secondary, Transition and Primitive 
rocks; and the Coastal Plain was represented as built up of Alluvian. 
In the other map, he showed the Piedmont region as composed of 
Eruptive and Metamorphic rocks, and the Coastal Plain of Creta- 
ceous. It will thus be seen that at the middle of the last century such 
little progress had been made in the stratigraphy of Cecil county 
that when Marcou came to sum up the results, he found the problem 
in about the same condition as when Maclure left it, almost fifty 
years before. 

In order to bring out with more clearness the progress which has 
been made in differentiating the various formations within Cecil 
county, they will be taken up in turn from this point, beginning 
with the oldest. 

The Crystalline Bocks of the Piedmont Plateau. 
The first report of Philip T. Tyson as State Agricultural Chemist 
of Maryland appeared in January, 1860. In this paper he published 
an able summary of the geology of Maryland, and indicated the 
position and extent of the various formations on a geological map. 
The crystalline rocks of Cecil county are represented on this map 



40 THE PHYSICAL FEATURES OF CECIL COUNTY 

in three colors, and are divided into Gneiss, Mica Slate, Hornblende 
Slate, Trap and Serpentine; thus representing the most complex series 
of rocks which had up to that time been distinguished. 

Professor Williams in 1887 commenced a reconnaissance of the 
crystalline rocks outside the Baltimore region which he liad already 
studied in great detail. During this season he traced the lines of the 
geological formations, particularly of the gabbro, northeastward 
across Harford county to the Susquehanna river and made some- 
what detailed sections along the Cecil county shore of the river. At 
the same time he traced the limits of the gabbro body of the region 
between Conowingo and the Octoraro eastward across part of Cecil 
county. The results of this preliminary survey were not published in 
detail but were mentioned in a report on the progress of the work on 
the Archasan geology of Maryland published the following year. The 
results of this trip served as a basis for a plan by which the crystalline 
rocks of Cecil and Harford counties were to be studied in detail by 
Professor Williams and his students. It was not, however, until 
1893 that detailed mapping was commenced in Cecil county. In this 
year Messrs. George P. Grimsley and Arthur G. Leonard commenced 
field studies of the granites and more basic rocks of the county. Mr. 
Grimsley published a report on the granites of Cecil county in 1894, 
in which he emphasizes the conclusions, that the granitic rocks are 
eruptive masses which have been modified by dynamic action and are 
probably older than the more basic rocks Avhich bound them on the 
north and south; that the granitic rocks are divided into two portions 
by a belt of staurolitic mica-schist; the rocks near Port Deposit being 
more gneissoid and foliated and hence representing either an older in- 
trusion or a zone of maximum dynamic action, while the changes in 
the northern divisions are mainly chemical resulting in a change of 
the feldspar to epidote; and that the staurolitic mica-schist separating 
the two areas of granite represents a sedimentary deposit more ancient 
than the granites, which probably owes its highly crystalline character 
to contact metamorphism. 

The work upon the basic rocks cnnunenced at the same lime by 
Mr. Leonard was not completed until some years later and the results 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE III. 




MARYLAND GEOLOGICAL SURVEY 41 

were not published until the fall of 1901. Dr. Leonard agrees with 
Dr. Grimsley in the view that the acid and basic rocks have broken 
through more ancient gneisses but differs from him in concluding 
that the basic and ultra-basic varieties have been cut by extensive 
dikes of granite and probably by the granite mass itself. It is con- 
sidered by him that there is a gradual passage of the granite into the 
diorite and that no line of separation can be drawn between them. 
His study of the geological relations and occurrences also seemed to 
show that the rocks of the area were not all formed at the same time 
but that the region was the scene of eruptive activity for a consider- 
able period during which the different types were produced. The 
norites and gabbros are regarded as the first to be erupted and 
the diorites as probably formed at the same or nearly the same time. 
The age of the granites is somewhat uncertain. It seems probable 
however, that they are younger than the norites and the diorites 
though the difference in age cannot be great. The most basic rocks, 
the peridotites and pyroxenites, were erupted at a later period than the 
norites and gabbros through which they have broken. Some of the 
pyroxenites, however, apparently form peripheral facies of the norite 
and probably belong to the same age as the latter. The pegmatites 
and acid dikes are younger than most of the peridotites and pyroxen- 
ites. Thus the whole complex of igneous rocks is thought by Dr. 
Leonard to consist of facies of a single magma uniting to form a 
geological unit, though it is not considered that this view requires 
the supposition that all of the rocks were formed either at the same 
time or by a continuous eruption. 

Prior to the completion of the detailed work on the basic rocks by 
Dr. Leonard the crystalline rocks of the entire county were mapped 
provisionally by Dr. Edward B. Mathews in the summer of 189 G and 
the results of this reconnaissance were shown in the geological map of 
Maryland published in Volume I of the reports of the Maryland Geo- 
logical Survey. 

The Potomac Group. 

The earliest paper of first rate importance on this subject was pub- 
lished by Professor George H. Cook in 1868. Cook at that time was 



42 THE PHYSICAL FEATURES OF CECIL COUNTY 

State Geologist of New Jersey and had been studying for some years 
the clay beds of the New Jersey Coastal Plain, which he grouped 
together under the name " Plastic clays." A continuation of these 
beds southward into Cecil county has shown them to be the youngest 
member of the Potomac series in that region. Following Cook, Pro- 
fessor R. P. Whitfield investigated the same beds from a paleonto- 
logic point of view, but called them Raritan clays, using the name sug- 
gested by Conrad in 1869; and a little later, Professor Newberry dis- 
cussed their flora but changed the name of the beds to Amboy clays. 

In the year 1884, Professor AV J McGee proposed for the first 
time the name " Potomac " for the great series of clays and sands 
which are now included in the Potomac group. McGee continued 
his work through a number of years and investigated the Potomac 
beds along the Atlantic Coast, publishing papers from time to time 
indicating the progress of the work, and finally summed up the salient 
results of his investigations in the most comprehensive paper of the 
series, entitled " Three Formations of the Middle Atlantic Slope." 
From this time there was no longer any doubt that the great deposits 
of clays and sands lying at the base of the Coastal Plain formations 
should be separated as a distinct group from the rest. 

Attempts were now made to subdivide the Potomac. Professor 
Philip R. Uhler, while McGee's work was still in progress, had also 
been engaged in the examination of that portion of the Potomac beds 
which lie within the Patapsco basin. His investigations led him to 
separate these beds into three members, termed, beginning with the 
oldest, Baltimorean, Albirupean, and Alternate Clay Sands. A few 
years later, in 1883, Darton separated the Magothy from the rest of 
the Potomac, and in 1885 Lester F. "Ward, who, for a number of 
years, had been carrying on an elaborate and minute examination of 
the Potomac beds, separated them into the James River series, the 
Rappahannock series, the Mt. Vernon series, the Aquia Creek series, 
the Iron Ore series and Albirupean series. While these Inter investi- 
gators were prosecuting their work, Professor W. B. Clark and Mr. 
A. Bibbins were also engaged in a most thorough study of the Poto- 
mac series throughout New Jersey, Delaware and Maryland. A 



MARYLAND GEOLOGICAL SURVEY 43 

preliminary paper setting forth the results of these investigations was 
published in 1895 under the joint authorship of Clark and Bibbins. 
In this contribution, the Potomac was, for the first time, separated into 
four well-marked formations which were natural in their sequence and 
capable of being cartographically represented. These were called, 
beginning with the oldest, the Patuxent, Arundel, Patapsco and 
Earitan formations. All of these formations, with the exception of 
the Arundel, are developed in Cecil county. 

Although the stratigraphy of the Potomac group seems now to be 
established on a firm basis, yet the age to which its various formations 
belong has not been definitely settled. Professor H. Carvill Lewis, as 
early as 1880, had assigned a white sand at the base of the Potomac 
beds near Elkton to the Jurassic and had correlated it with the 
" Hastings Sand." A few years later, in 1889, Fontaine assigned the 
Potomac to the younger Mesozoie, and Marsh the same year main- 
tained that the Potomac beds in Maryland were Upper Jurassic. 
McGee and others, however, believed that the series belonged to the 
Cretaceous. This question was in rather an unsettled state when it 
was revived by Marsh in 1896, who again claimed that the Potomac 
should be assigned to the Jurassic on the evidence derived from 
certain vertebrate remains found within it in the State of Maryland 
which were regarded as Jurassic in age. This announcement by 
Marsh precipitated a lively discussion, which was participated in by 
Messrs. Gilbert, Marcou, Hollick, Hill and Ward. The question was 
still under discussion when Clark and Bibbins brought out the above- 
mentioned paper. It was found on careful examination that the 
lower two members, the Patuxent and Arundel formations, carried 
mainly monocotyledons with a few dicotyledons of somewhat primitive 
type. It was in these beds that Marsh had discovered the vertebrate 
remains, which he referred to the Jurassic. Above, in the Patapsco 
and the Raritan, dicotyledonous leaves appeared more abundantly, 
and the flora had a much more modern aspect. It then seemed 
probable that the Potomac beds belonged to two distinct ages, and 
accordingly the Patuxent and Arundel have been referred question- 
ably to the Jurassic while the Patapsco and Raritan are believed to be 
Lower Cretaceous. 



44 THE PHY8ICAL FEATURES OF CECIL COUNTY 

The Upper Cretaceous Formations. 

To Professor George H. Cook is due the credit for first differentiat- 
ing the Upper Cretaceous beds of the Atlantic Coastal Plain. In 
1 s r»4, Cook announced that the Coastal Plain deposits contained three 
distinct beds of marl, a discovery which he elaborated considerably at 
a later period, for in 1868 he announced that the Coastal Plain of 
New Jersey carried the following beds: Clay Marl, Lower Marl, 
Red Sand, Middle Marl, Yellow Sand and Upper Marl. Before this 
announcement had been made, however, Philip T. Tyson had dis- 
covered the presence of Cretaceous beds in Maryland and had mapped 
them in Cecil county, although he did not determine their sub- 
divisions. 

Uhler and Darton later also took part in the discussion, but con- 
fined their work mostly to the Cretaceous as developed on the western 
shore of Maryland. Darton named it in part the " Severn formation," 
and noted its presence on Elk Neck in Cecil county. 

In 1891, Professor Clark took up the investigation of the Upper 
Cretaceous formations of New Jersey where Professor Cook had 
left it. He prepared, in 1S92, a map of Monmouth county, New 
Jersey, in which Cook's terms w r ere used, but in 1893 he abandoned 
Cook's nomenclature and substituted the following: Matawan forma- 
tion = Clay Marl; Navesink formation = Lower Marl; Red Bank 
formation = Bed sand; Bancocas formation = Middle Marl; Manas- 
quan formation = Upper Marl. In 1894, he announced the continu- 
ation of many of these formations southward through New Jersey into 
Maryland, and in 1897 published, with P. M. Bagg and G. B. Shat- 
tuck as collaborators, a summary of the investigations which had been 
carried from Atlantic Highlands to the Potomac river. This paper 
was accompanied by two maps which showed the distribution of the 
Cretaceous over the entire area. As the work was extended south- 
ward, it seemed accessary to unite the Navesinkand Red Bank forma- 
tions into one member, which was known as the Monmouth formation. 
The .Matawan, Monmouth and Pancocas formations were all repre- 
sented on the map as present in Cecil county. 



MARYLAND GEOLOGICAL SURVEY 45 

The Tertiary Formations. 

The only formations belonging to the Tertiary in Cecil county are 
the Aquia, which is Eocene, and possibly the Lafayette, which is re- 
ferred provisionally to the Pliocene. As far back as 1830, Conrad 
had discovered' and described a few Eocene forms from Southern 
Maryland, and the formations which carried them at Fort Washing- 
ton he had referred to the " London Clay." Three years later, Isaac 
Lea published his " Contribution to Geology," in which for the first 
time the term " Eocene " was applied to the lower portion of the 
Tertiary deposits. All this work, however, was carried on well out- 
side the limits of Cecil county. After the year 1850, there was little 
done in the Tertiary geology of Maryland for 25 years. When work 
was once more resumed, Heilprin took an active part in the discussion 
by his contributions to the Eocene paleontology and by his correla- 
tion of the Eocene deposits of Maryland and Virginia with horizons 
in Europe. Darton traced the Eocene northward under the name 
of Pamunkey, and in 1890 announced its presence along the northern 
bank of the Sassafras river. Six years later, Professor Clark brought 
out an extensive monograph on the Eocene deposits of the Middle 
Atlantic Slope, in which he noted the presence of Eocene along the 
northern bank of the Sassafras river, and described at great length 
the paleontology of the Eocene as developed in Maryland, Delaware 
and Virginia. In 1901, Clark and Martin published an exhaustive re- 
port on the Eocene deposits of Maryland. In this paper the Eocene 
is subdivided into the Nanjemoy and Aquia formations, and the latter 
is indicated as present along the northern bank of the Sassafras river 
in Cecil county. 

The separation of the Lafayette formation in Cecil county was also 
going forward while the Eocene stratigraphy was being studied. 
McGee, in 1888, announced the Appomattox formation as extending 
from Virginia to the Potomac river, and in 1891 Darton announced 
the continuation of this formation northward across Maryland, and 
mapped it as developed in isolated patches along the eastern margin of 
the Piedmont Plateau and also occupying portions of the Coastal 
Plain from the Potomac river to the head of Chesapeake Bay. A 



40 THE PHYSICAL FEATURES OF CECIL COUNTY 

little later, the Appomattox formation of McGee was correlated with 
Ililgard's Lafayette, and the extension of the latter across Maryland 
into Cecil county was thus established. 

The Columbia Group. 

The presence of surficial deposits in Cecil county and neighboring 
regions was noted by the early geologists and discussed in a desultory 
manner by them, but the differentiation of these deposits and the 
determination of their natural sequence has been the work of the 
last twenty years. To Professor W J McGee is due the credit for 
first grouping these surficial deposits by themselves under the name 
of Columbia and of pointing out many of their leading characteristics. 

He divided the Columbia into two phases, fluvial and inter-fluvial. 
The fluvial phase was composed of deltas which were deposited under 
water, by those streams in whose valleys they now lie, when the land 
stood lower than it does to-day. The inter-fluvial phase was found 
on the divides and was a littoral deposit made by the waves which beat 
against the coast at the same time the rivers were building their deltas. 
The two phases were therefore contemporaneous and graded over 
into one another. The fluvial phase exhibited a distinct bi-partite 
division. The upper member consisted of a brick-clay and loam, and 
the lower member was composed of sand, gravel and huge boulders. 
McGee found the material as a whole, coarser near the mouths of the 
gorges whore the rivers leave the Piedmont Plateau to pass into the 
Coastal Plain than in the more remote portions of the delta. The 
inter-fluvial phase possessed no such regularity of bedding, but was 
indiscriminately composed of clay, sand and gravel largely of local 
origin. These delta deposits were identified in all the principal river- 
of the Middle Atlantic slope and are particularly well developed in 
the valleys of the Potomac, Susquehanna and Delaware. Due to the 
presence of these huge boulders, which were evidently ice-borne and 
indicated a climate much colder than exists to-day in the same region, 
as well as to the fact that the Columbia, when traced northward, was 
found to pass under the terminal moraine, it was concluded that it 
was Quaternary in age and belonged to the earlier glacial advance. 



MARYLAND GEOLOGICAL SURVEY 47 

McGee concluded that these beds, since their deposition, had been 
raised and tilted so that they now lie higher in the regions to the 
north than they do further south. Their present elevation was found 
to be about 500 feet along the gorge of the Susquehanna and 245 feet 
at its mouth ; 400 feet on the upper Delaware ; 145 feet on the Poto- 
mac; 125 feet on the Rappahannock; 100 feet on the James and 75 
feet on the Roanoke. A series of well-defined terraces distributed 
over the entire region was also noted. Professor McGee also pub- 
lished an interesting paper on " The Geology of the Head of Chesa- 
peake Bay," in which he called attention to some of the more striking 
features of the Columbia formation within Cecil county. 

Mr. 1ST. H. Darton took up the work where McGee left it. The 
Columbia was found to lie divisible into an earlier and a later mem- 
ber, which were developed in well-defined terraces, the former lying 
normally above the latter. The land surface upon which the Colum- 
bia was deposited had been raised and tilted at various times in such 
a manner that only in that part of the Coastal Plain which lies near 
the Piedmont was the normal sequence present, while in that portion 
bordering on Chesapeake Bay the normal sequence was reversed. 
This state of things was brought about in the following way: At the 
close of the Lafayette deposition, the surface on which that formation 
rested was raised and tilted so as to slope eastward toward the sea. 
Later, after suffering considerable erosion, it was depressed in such a 
manner that its eastern portion was submerged while its western 
margin bordering the Piedmont Plateau remained above water. In 
the estuaries thus formed and along the coast, the earlier Columbia 
formation was then deposited. This formation, therefore, built up 
a terrace below that of the Lafayette in the heads of the estuaries 
near the Piedmont, but covered up the Lafayette surface where it was 
submerged to the east. While the deposition of the earlier Columbia 
was still in progress, the Coastal Plain again tilted so as to bring that 
portion of it lying to the northeast and against the Piedmont above 
water, while the southeastern portion was still further depressed. 
The later Columbia was in its turn deposited in the estuaries beneath 
the earlier Columbia where the latter had been elevated, and above 



48 THE PHYSICAL FEATURES OF CECIL COUNTY 

it where it had been depressed. Consequently the three formations 
near the Piedmont were developed in separate terraces lying one 
above the other, the Lafayette at the top, with the earlier Columbia 
in the middle and the later Columbia at the bottom, while in the 
eastern submerged portion the formations were not developed in 
terraces, but in a continual series, with an erosive break between the 
Lafayette and the earlier Columbia. In this region the sequence ran, 
beginning at the top, later Columbia, earlier Columbia, and Lafayette. 

Professor P. D. Salisbury has been engaged for the last ten years 
in the investigation of a similar series of deposits in New Jersey. 
His interpretation of the surficial deposits in that state has led him to 
divide them, beginning with the oldest, into the Bridgeton, Pensauken 
and Cape May formations and a high level loam. It has been found, 
however, that the classification adopted by the New Jersey Surveys 
11 p to May, 1901, could not be applied to the surficial deposits as 
interpreted in Maryland. 

In May, 1901, the writer published a paper on " The Pleistocene 
Problem of the North Atlantic Coastal Plain." In this com- 
munication, the work of previous investigators was summarized 
and compared, and the conclusions which the author had reached in 
his study of the Columbia deposits of Maryland were given at some 
length. As these conclusions are discussed below, they will not be 
reviewed in this place, other than to say that the Columbia was 
divided, beginning with the oldest, into the Sunderland, Wicomico 
and Talbot formations, which were described as developed in terraces 
lying one ;ibove the other and separated by well-pronounced scarp 
lines. Several months after this paper had been published, another 
contribution on the same subject by Professor P. D. Salisbury ap- 
peared in the Report of the State Geologist of New Jersey for 1900. 
This paper carries the date of November, 1900, but embodied in 
its text are certain formational names applied to the classification of 
the Columbia deposits in Maryland which were not published before 
May, 1901, and one of them not even suggested before that date; it 
would therefore seem that an error must have crept into the dating 
of Professor Salisbury's paper. 



MARYLAND GEOLOGICAL SURVEY 49 



BIBLIOGRAPHY. 

CONTAINING REFERENCES TO THE GEOLOGY AND ECONOMIC RESOURCES OF 

CECIL COUNTY. 

1624. 

Smith, John. A Generall Historie of Virginia. New England, and 
the Summer Isles, etc. London, 1621. [Several editions.] 

(Repub.) The True Travels, Adventures and Observations of Captaine 
Iohn Smith in Europe, Asia, Afrika, and America, etc. Richmond, 1819, 2 
vols. — from London edition of 1629. 

Pinkerton's Voyages and Travels, vol. 13, London, 1812, 4to, pp. 1-253 — 
from London edition of 1624. 

Eng-. Scholars Library No. 16. (For bibliography of Smith's works and 
their republication, see pp. cxxx-cxxxii.) 

1778. 

Burnaby, Andrew. Travels through the Middle Settlements in 
North America in the years 1759 and 1760; with observations upon the 
State of the Colonies. 

(Repub.) Pinkerton's Voyages and Travels, vol. xiii, London. 1812, pp. 
701-752. 

1784. 
Swedenborg, Emanual. Regnum Subterraneum sive Minerale de 
Ferro. [etc.] Dresdae et Lipsiae. MDCCLXXXIV. 

1796. 
Carey, M. Carey's American Pocket Atlas containing the follow- 
ing maps, viz. . . . with a concise Description of each State. Phila., 
1796. 12mo. 118 pp. 

1807. 

Scott, Joseph. A Geographical description of the states of Mary- 
land and Delaware. Phila., lumber, Conrad & Co., 1807. 

1809. 

Latrobe, B. H. An account of the Freestone Quarries on the 
Potomac and Rappahannock rivers. (Eead Feb. 10, 1807.) 

Trans. Amer. Phil. Soc, o. s. vol. vi, 1809, pp. 283-293. 

Maclure, Wm. Observations on the Geology of the United States, 
explanatory of a Geological Map. (Read Jan. 20, 1809.) 

Trans. Amer. Phil. Soc, o. s. vol. vi, 1809, pp. 411-428. 
4 



50 THE PHYSICAL FEATURES OF CECIL COUNTY 

Maclure, Wm. Observations sur la Geologie des Etats-Unis, sur- 
vant a expliquer une Carte Geologique. 

Journ. de phys. de chim. et d'hist. nat. tome lxix, 1809, pp. 204-213. 

1811. 

Maclure, Wm. Suite des observations sur la Geologie des Etats- 
Unis. 

Journ. de phys., de chim. et d'hist. nat., tome lxxii, 1811, pp. 137-165. 

1817. 

Maclure, Wm. Observations on the Geology of the United States 
of America, with some remarks on the effect produced on the nature 
and fertility of soils by the decomposition of the different classes of 
rocks. With two plates. Phila., 1817. 12mo. 

Republished in Trans. Amer. Phil. Soc., n. s., vol. i, 1S18, pp. 1-91. 

Leon. Zeit., vol. i, 1826, pp. 124-138. 

1818. 

Mitchill, Samuel L. Cuvier's Essay on the Theory of the Earth. 
To which are now added Observations on the Geology of North Amer- 
ica, New York, 1818. 8vo. 431 pp., plates. 

1828. 

Carpenter, George W. On the Mineralogy of Chester County, 

with an account of some of the Minerals of Delaware, Maryland and 

other Localities. 

Amer. Jour. Sci., vol. xiv, 1828, pp. 1-15. 

Also published separately, 12mo, 16 pp., Phila., 1S28 (Md. ref., p. 14). 

1829. 
Livermore & Dexter. A collection of fossil earths, and minerals 
from the deep cut of the Delaware and Chesapeake Canal, with memoir 
and profile of geological strata developed in progress of work. 

Proc. Amer. Phil. Soc., vol. xxii (2), 1884, p. 594. 
Mentioned in Minutes Proc. Amer. Phil. Soc, 1743-1838. 

1830. 

Morton', Samuel G. Synopsis of the Organic Eemains of the Fer- 
ruginous Sand Formation of the United States, with Geological 
remarks. 

Amer. Jour. Sci., vol. xvii, 1830, pp. 274-295; vol. xviii, 1830, pp. 243-250. 



MARYLAND GEOLOGICAL SURVEY 51 

1831. 

Brongniart, Alex. Rapport sur un Memoire de M. Dufresnoy, 
Ingenieur cles Mines, ayant pour titre: Des Caracteres particuliers 
que presente le terrain de Craie dans le Sud de la France et sur les 
pentes des Pyrenees. Fait a l'Acad. roy. d. Sci., Apr. 1831. 

Annales des Sc. Naturelles, t. xxii, 1831, pp. 436-463, Plate XIV. 

1832. 

Durand, Elias. On the Green Color and Nature of the coloring 
Agent of the Water of the Delaware and Chesapeake Canal, near the 
first lock on the Chesapeake side. 

Jour. Phila. Col. of Pharmacy, vol. iii, 1832, pp. 276-277. 

Morton, S. G. On the analogy which exists between the Marl of 
New Jersey, &c, and the Chalk formation of Europe. 

Amer. Jour. Sei., vol. xxii, 1832, pp. 90-95. 

Also published separately. 

1833. 

Finch, J. Travels in the United States of America and Canada. 
London, 1833. 8vo. 455 pp. 

1831. 

Ducatel, J. T., and Alexander, J. H. Report on the Projected 
Survey of the State of Maryland, pursuant to a resolution of the Gen- 
eral Assembly. Annapolis, 1831. 8vo. 39 pp. Map. 

Md. House of Delegates, Dec. Sess., 1833, 8vo, 39 pp. 

Another edition, Annapolis, 1834, 8vo, 58 pp., and map. 

Another edition, Annapolis, 1834, 8vo, 43 pp., and folded table. 

Amer. Jour. Sci., vol. xxvii, 1835, pp. 1-38. 

Morton, S. G. Synopsis of the organic remains of the Cretaceous 
group of the United States. To which is added an appendix contain- 
ing a tabular view of the Tertiary fossils hitherto discovered in North 
America. Phila., 1831. 8vo, 88 pp. 

(Abst.) Amer. Jour. Sci., vol. xxvii, 1835, pp. 377-381. 

1835. 

Ducatel, J. T. Geologist's report 1834. pp. 84. 

[Another edition.] Report of the Geologist to the Legisla- 
ture of Maryland, 1831. n. d. 8vo, 50 pp. 2 maps and folded tables. 

Ducatel, J. T., and Alexander, J. H. Report on the New Map of 
Maryland, 1834, [Annapolis] n. d. 8vo, 59, i, pp. Two maps and one 
folded table. 

Md. House of Delegates, Dec. Sess., 1834. 



52 THE PHYSICAL FEATURES OF CECIL COUNTY 

1836. 

Ducatel, J. T. Report of the Geologist, n. d. 8vo, pp. 35-84. 

Plate. 

Separate publication (see Ducatel and Alexander). 

Dttcatel, J. T., and Alexander, J. H. Report on the New Map of 

Maryland. 1835. 8vo, 81. 1 pp. [Annapolis, 1836.] 

Md. Pub. Doc, Dec. Sess., 1835. 

Another edition, 96, 1 pp. and maps and plate. 

Engineer's Eeport, pp. 1-34; Eeport of the Geologist, pp. 35-84. 

■ — Report of the Engineer and Geologist in relation to the New 

Map to the Executive of Maryland. 

Md. Pub. Doc., Dec. Sess., 1835 [Annapolis, 1836], 8vo, 84, 1 pp., 6 maps 
and plates. 

(Rev.) Amer. Jour. Sci., vol. xxx, 1836, pp. 393-394. 

Jour. Franklin Inst., vol. xviii, n. s. 1836, pp. 172-178. 

1837. 

Ducatel, J. T. Outline of the Physical Geography of Maryland, 
embracing its prominent Geological Features. 

Trans. Md. Acad. Sci. and Lit., vol. ii, 1837, pp. 24-54, with map. 

Ducatel, J. T., and Alexander, J. II. Report on the New Map of 

Maryland, 1836. [Annapolis, 1837.] 8vo, 101 pp. and 5 maps. 

Md. House of Delegates, Sess. Dec, 1836. 
Another edition, 117 pp. 

Tyson, Philip T. A descriptive Catalogue of the principal minerals 
of the State of Maryland. 

Trans. Md. Acad. Sci. and Lit., 1837, pp. 102-117. 

1838. 

Ducatel, J. T. Annual Report of the Geologist of Maryland. 1837. 
[Annapolis, 1838.] Svo. 39, ] pp, and 2 maps. 
Md. Pub. Doc, Dec. Sess., 1837. 

1839. 

Ducatel, J. T. Annual Reporl of the Geologist of Maryland. 1838. 
[Annapolis, 1839.] Svo, map and illustrations. 33 pp. 

Md. Pub. DOC, Dec Sess., 1838. 



MARYLAND GEOLOGICAL SURVEY 53 

1845. 

Lyell, Chas. Travels in North America, with Geological Observa- 
tions on the United States, Canada and Nova Scotia. New York, 1845. 
2 vols. 12mo. 

Another edition, London, 1845, 2 vols., 12mo. 

Second English edition, London, 1S55. 

German edition, translated by E. T. Wolff, Halle, 1846. 

1850. 

Higgins, Jas. Eeport of James Higgins, M. D., State Agricultural 
Chemist, to the House of Delegates. Annapolis, 1850. 8vo. 92 pp. 
Md. House of Delegates, Dec. Sess. [G]. 

1852. 

Desor, E. Post Pliocene of the Southern States and its relation 
to the Laurentian of the North and the Deposits of the Valley of the 
Mississippi. 

Amer. Jour. Sci., 2nd ser., vol. xiv, 1852, pp. 49-59. 

Fisher, E. S. Gazetteer of the State of Maryland compiled from 
the returns of the Seventh Census of the United States. New York 
and Baltimore, 1852, 8vo, 122 pp. 

Lyell, Chas. Travels in North America, in the years 1841-2; with 
Geological Observations on the United States, Canada, and Nova Scotia. 
New York, 1852. 2 vols. 

1853. 

Conrad, T. A. Descriptions of New Fossil shells of the United 
States. 

Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. ii, 1853, pp. 273-276. 

1858. 

Marcou, J. Geology of North America. Zurich, 1858. 4to. 

Eogers, H. D. The Geology of Pennsylvania. Phila., 1858. 4to. 
2 vols. [vol. II in two parts] and maps. 

1859. 

Gabb, W. M. Description of some new Species of Cretaceous 
Fossils. 

Jour. Acad. Nat. Sci., Phila., 2nd ser., vol. iv, 1S5S-1860, pp. 299-305. 



54 THE PHYSICAL FEATURES OF CECIL COUXTY, 

Rogers, H. D. Classification of the Metamorphic Strata of the 
Atlantic Slope of the Middle and Southern States. (Read Feb. 18, 
1857.) 

Proc. Boston Soc. Nat. Hist., vol. vi, 1859, pp. 140-145. 

1860. 

Tyson, Philip T. First Report of Philip T. Tyson, State Agri- 
cultural Chemist, to the House of Delegates of Maryland, Jan. 1860. 
Annapolis, 1860. 8vo. 145 pp. Maps. 

Md. Sen. Doc. [E]. Md. House Doc. [C]. 

Report of Chemist, n. d. (1860), 8vo, 4 pp. 

1862. 
Tyson, Philip T. Second Report of Philip T. Tyson, State Agri- 
cultural Chemist, to the House of Delegates of Maryland, Jan. 1862. 
Annapolis, 1862. 8vo. 92 pp. 
Md. Sen. Doc. [F]. 

1867. 

Higgixs, James. A Succinct Exposition of the Industrial Resources 
and Agricultural advantages of the State of Maryland. 
Md. House of Delegates, Jan. Sess., 1867 [DD], 8vo, 109, iii pp. 
Md. Sen. Doc, Jan. Sess., 1867 [U]. 

1871. 
Siialer, X. S. Some Physical Features of the Appalachian System 
and the Atlantic Coast of the United States, especially near Cape Hat- 
teras. (Read Feb. 1, 1871.) 

Ann-r. Nat., vol. v, 1871, pp. 178-183. 

1874. 
DUNLAP, Tnos. (Editor). Wiley's American Iron Trade Manual. 
New York, 1S74. 

1875. 
(i ii.i.moim:. Q. A. Report on the Compression Strength, Specific 
Gravity, and ratio of Absorption of the Building stones in the United 
States. 

Kept. Chief of Engineers U. S. Army, part ii, appendix II, pp. 819-S51. 
Same separately, 8vo, 37 pp., New York, Van Nostrand, 1876. 

Toner, Joseph M. Contributions to the Medical History and Phys- 
ical Geography of Mary la ml. 

Trans. Med. and Chirurg-ical Faculty of Md., Baltimore, 1875. 



MARYLAND GEOLOGICAL SURVEY 55 



1876. 



Hachewelder, John (W. C. Reichil, editor). Names which the 
Lenni Lennapi or Delaware Indians gave to Rivers, Streams and Local- 
ities within the states of Penn., New Jersey, Maryland and Virginia, 
with their signification. Nazareth, 1872. 

Trans. Moravian Hist. Soc, vol. i, Nazareth, 1876, pp. 225-282. 

Originally published 1834, Trans. Amer. Phil. Soc. (title spelled differently). 

1877. 

Lewis, H. C. On the Optical Characters of some Micas. 

Printed from Proc Min. and Geol. Sect. Acad. Nat. Sci., Phila., Oct. 22, 1877. 

1878. 

Lesley, J. P. [On Orthoceras from Frazer Point on the Susque- 
hanna.] 

Proc. Amer. Phil. Soc, vol. xvii, 1878, p. 312. 

1879. 

Frazer, Persifor, Jr. Fossil (?) Forms in the Quartzose Rocks 
of the Lower Susquehanna, with plate. (Read Apr. 4, 1879.) 
Proc. Amer. Phil. Soc, vol. xviii, 1880, pp. 277-279. 

1880. 

Frazer, Persifor, Jr. The Geology of Lancaster County, Pa. 
Kept. 2nd Geol. Surv. Pa. CCC, Harrisburg, 1880, atlas. 

Lewis, H. C. On Jurassic Sand. 

Proc Acad. Nat. Sci., Phila., vol. xxxii, 1880, p. 279. 

1881. 

Johnston, George. History of Cecil County, Maryland, and the 
early settlements around the head of Chesapeake Bay and on the dela- 
ware river, with sketches of some of the old families of Cecil County. 
Elkton, 1881. 8vo. 548 pp., i-xii map. 

1883. 

Lesley, J. P. The Geology of Chester County, Pennsylvania. 
Eept. 2nd Geol. Surv. of Pa. C-4, Harrisburg, 1883. 

Smock, J. C. The Useful Minerals of the United States. 
Mineral resources U. S., 1882, Washington, 1883, pp. 664, 690-693. 



56 



THE PHYSICAL FEATURES OF CECIL COUNTY 



Uhler, P. E. Geology of the Surface Features of the Baltimore 
Area. 

Johns Hopkins Univ. Cir. No. 21, vol. ii, 1883, pp. 52-53. 
(Abst.) Science, vol. i, 1883, pp. 75-76, 277. 

Wilbur, F. A. Marls. 

Mineral Kesources U. b., 1882, Washington, 1883, p. 522. 

Clay. 

Mineral Kesources U. S., 1882, Washington, 1883, pp. 405-475. 

1884. 

Adams, W. H. The Pyrites Deposits of Louisa County, Ya. 
Trans. Amer. Inst. Min. Eng., vol. xii, 1884, pp. 527-535. 
Chester, Frederick D. The Quaternary Gravels of Northern Dela- 
ware and Eastern Maryland, with map. 

Amer. Jour. Sci., 3rd ser., vol. xkvii, 1884, pp. 189-199. 

Huntington, J. H., Monroe, Chas. E., Singleton, H. K. De- 
scriptions of Quarries and Quarry Eegions compiled from notes of 
Messrs. Huntington, Monroe and Singleton. 

Tenth Census, vol. x, Washington, 1884, pp. 175-179. 

Smock, J. C. Geologico-geographical Distribution of the Iron Ores 
of the Eastern United States. 

Eng. and Min. Jour., vol. xxxvii, New York, 1S84, pp. 217-218, 230-232. 
Trans. Inst. Min. Eng., vol. xii, 1884, pp. 130-144. 

Swank, James M. History of the Manufacture of Iron in all Ages. 
Phila., 1884. 

1885. 

Chester, Frederick D. The Gravels of the Southern Delaware 
Peninsula. 

Amer. Jour. Sci., 3rd ser., vol. xxix, 1885, pp. 30-44. 

Kunz, G. F. Precious Stones. 

Mineral Resources U. S., 1883-84, Washington, 1885.. 

1886. 

McGee, W J Geography and Topography of the head of Chesa- 
peake Bay. (Read to Amer. Assoc. Adv. Sci., 1886.) 

(Abst.) Amer. Jour. Sci., 3rd ser., vol. xxxii, 1886, p. 323. 

Pumpelly, R. Geological and Geographical distribution of the Iron 
Ores of the United States. 

Tenth Census, vol. xv, Mining Industries of the U. S., Washington, 1886, 
pp. 3-36. 



MAE YL AND GEOLOGICAL SURVEY 57 



1887. 



McGee, W J The Columbia Formation. 

Proc. Amer. Assoc. Adv. Sci., vol. xxxvi, 1887, pp. 221-222. 

1888. 

Day, D. T. (Editor). Useful Minerals of the United States. 
Mineral Resources U. S., 1887, Washington, 1S8S, pp. 739-742. 

McGee, W J The Geology of the Head of Chesapeake Bay. 

7th Ann. Eept. U. S. Geol. Surv., 1885-86, Washing-ton, 1888, pp. 537-646, 
plates 56-71. 

(Abst.) Amer. Geol., vol. i, 1S87, pp. 113-115. 

Three Formations of the Middle Atlantic Slope. 

Amer. Jour. Sci., 3rd ser., vol. xxxv, 1888, pp. 120-143, 328-331, 367-388, 448- 
466, plate ii. 

(Abst.) Nature, vol. xxxviii, 1888, pp. 91, 190. 
Amer. Geol., vol. ii, 1SS8, pp. 129-131. 

Uhler,, P. E. The Albirupean Formation and its nearest relatives 
in Maryland. 

Proc. Amer. Phil. Soc, vol. xxv, 1888, pp. 42-53. 

Observations on the Eocene Tertiary and its Cretaceous 

Associates in the State of Maryland. 
Trans. Md. Acad. Sci., vol. i, 1888, pp. 11-32. 

Williams, George H. Progress of Work on the Archean Geology 
of Maryland. 

Johns Hopkins Univ. Cir. No. 65, vol. vii, 1888, pp. 61-63. 

1889. 
Fontaine, W. M. Potomac or Younger Mesozoic Flora. 

Mono. U. S. Geol. Surv., No. 15, 1SS9, 377 pp., ISO plates. 

House Misc. Doc, 50th Cong-., 2nd sess., vol. xvii. No. 147. 

(Rev.) Amer. Jour. Sci., 3rd ser., vol. xxxix, 1890, p. 520 (L. F. W.). 

Uhler, P. E. Additions to observations on the Cretaceous and 
Eocene formations of Maryland. 

Trans. Md. Acad. Sci., vol. i, 1889, pp. 45-72. 

Ward, Lester F. The Geographical Distribution of Fossil Plants. 
Sth Ann. Kept. U. S. Geol. Surv., 1886-87, Washington, 1889, part ii, pp. 
663-960, maps. 



58 THE PHYSICAL FEATURES OF CECIL COUNTY 

1890. 
Chester, F. D. The Gabbros and Associated Eocks in Delaware. 

Bull. U. S. Geol. Surv. No. 59, Washington, 1890. 

House Misc. Doc, 51st Cong., 1st sess., vol. xxxii, No. 244. 

(Abst.) Amer. Nat., vol. xxv, p. 1002. 

Day, D. T. Structural Material. 

Mineral Resources U. S., 1888, Washington, 1890. 

M.v< i aim. \\ i-:, J. R. An American Geological Railway Guide. 

Appleton, 1890. 2nd edit. 8vo, 426 pp. 

Dhler, P. R. Notes on Maryland. 

Maefarlane's An American Geol. R. R. Guide, 2nd edit., Appleton, 1S90. 

1891. 
Daktox, N H. Mesozoic and Ccnozoic Formations of Eastern Vir- 
ginia and Maryland. 

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 431-450, map, sections. 
(Abst.) Amer. Geol., vol. vii, 1891, p. 185. 
Amer. Nat., vol. xxv, 1891, p. 658. 

Lindenkohl, A. Notes on the submarine channel of the Hudson 
river and other evidences of postglacial subsidence of the middle Atlan- 
tic coast region. 

Amer. Jour. Sci., 3rd ser., vol. xli, 1891, pp. 489-499, 18 plates. 

Mr(ii;]:, W J The Lafayette Formation. 

12th Ann. Rept. U. S. Geol. Surv., 1890-91, Washington, 1891, pp. 347-521. 

Merrill, G. P. Stones for Building and Decoration. Wiley, 
New York, 1891. 8vo. 453 pp. 

1892. 

CLARK, Wm. B. The Surface Configuration of Maryland. 
Monthly Rept, Md. State Weather Service, vol. ii, 1892, pp. 85-89. 
Dana, E. S. Manual of Mineralogy. Wiley, New York, 1892. 
1134 pp. 

Dartox, N. H. Physiography of the region [Baltimore and vicin- 
ity] and Geology of the Sedimentary Rocks. 

Guide to Baltimore with an account of the Geology of its Environs, and 
three maps. 

Baltimore, 1892, pp. 123-139. 

S(ii\i!i\ .1. Thomas. The Natural Resources and advantages of 

Maryland, being a complete description of all of the counties of the 

State and the City of Baltimore. Annapolis, 1892. 

UhleR, P. R. AIl)irii|te;in Studies. 
Trans. Md. Acad. Sci., vol. i. 1S90-92, pp. 185-202. 



MARYLAND GEOLOGICAL SURVEY 59 

1893. 

Anon. General Mining News — Maryland. 
Eng. and Min. Jour., vol. lvi, 1893, p. 404. 

Clark, W. B. Physical Features [of Maryland]. 

Maryland, its Resources, Industries and Institutions, Baltimore, 1893, pp 
11-54. 

Darton, N. H. The Magothy Formation of Northeastern Maryland. 
Amer. Jour. Sci., 3rd ser., vol. xlv, 1893, pp. 407-419, map. 

Day, Wm. C. Stone. 

Mineral Resources U. S., 1891, Washing-ton, 1893. 

Stone. 

Mineral Resources U. S., 1892, Washington, 1893. 

Hill, R. T. Clay Materials of the United States. 
Mineral Resources U. S., 1891, Washing-ton, 1893. 

Keyes, C. E. Some Maryland Granites and their Origin. (Read 

Dee. 1892.) 

Bull. Geol. Soc. Amer., vol. iv, 1893, pp. 299-304, plate x. 

Keyser, W. Iron. 

Maryland, its Resources, Industries and Institutions, pp. 100-112, Balti- 
more, 1893. 

Whitney, Milton. The Soils of Maryland. 

Md. Agri. Exper. Sta., Bull. No. 21, Colleg-e Park, 1893, 5S pp., map. 

Williams, G. H. Mines and Minerals [of Maryland]. 
Maryland, its Resources, Industries and Institutions, Baltimore, 1893, 
pp. 89-153. 

, and Clark, W. B. Geology [of Maryland]. 

Maryland, its Resources, Industries and Institutions, Baltimore, 1893, pp. 
55-89. 

1S94. 

Clark, Wm. Bullock. The Climatology and Physical Features of 
Maryland. 

1st Biennial Rept. Md. State Weather Service, 1894. 

Grimsley, G. P. Granites of Cecil County in Northeastern Mary- 
land. 

Jour. Cincinnati Soc. Nat. Hist., vol. xvii, 1894, pp. 56-67, 87-114. 
Also published separately. 

Maryland State Weather Service. The Climatology and Phy- 
sical Features of Maryland. 

First Biennial Report of the Maryland State Weather Service for the years 
1892 and 1893. Baltimore, 1894. 



60 THE PHYSICAL FEATURES OF CECIL COUNTY 

1895. 

Clark, Wm. B. Cretaceous Deposits of the Northern Half of the 
Atlantic Coastal Plain. 

Bull. Geol. Soc. Amer., vol. vi, 1895, pp. 479-4S2. 

Keyes, C. E. Acidic Eruptives of Northeastern Maryland. 
Amer. Geol., vol. xv, 1895, pp. 39-46. 

Boberts, D. E. Xote on the Cretaceous Formations of the Eastern 
Shore of Maryland. 

Johns Hopkins Univ. Cir. No. 121, vol. xv, 1S95, p. 16. 

Ward, Lester F. The Potomac Formation. 

15th Ann. Eept. U. S. Geol. Surv., 1893-94, Washington, 1S95, pp. 307-397, 
plates. 

1896. 
Dartox, X. H. Artesian Well Prospects in the Atlantic Coastal 
Plain Eegion. 

Bull. IT. S. Geol. Surv. No. 13S, 1S96, 228 pp., 19 plates. 
House Misc. Doc, 54th Cong., 2nd sess., vol. xxxv, No. 28. 

Kxowltox, F. H. American Amber-producing Tree. 
Science, n. s., vol. iii, 1896, pp. 582-584. 

1897. 
Bauer, L. A. First Eeport upon the Magnetic Work in Maryland, 
including the History and Objects of Magnetic Surveys. 
Aid. Geol. Surv., vol. i, 1897, pp. 403-529, plates xiv-xvii. 

( i.\i;k, Wm. Bullock. Historical sketch, embracing an Account of 
the Progress of Investigation concerning the Physical Features and 
Natural Eesources of Maryland. 

Md. Geol. Surv., vol. i, 1897, pp. 4S-13S, plates ii-v. 

Outline of Present Knowledge of the Physical Features of 

Maryland. 

Ibid., vol. i, 1S97, pp. 139-228, plates vi-xiii. 

, with the collaboration of E. M. Bagg and George B. Shat- 

tuck. LTpper Cretaceous Formations of Xew Jersey, Delaware, and 
Maryland. 

Bull. Geol. Soc. Amer., vol. viii, 1897, pp. 315-35S, plates xl-1. 

and Arthur Biijmxs. The Stratigraphy of the Potomac 

Group in Maryland. 

Jour, of Geol., vol. v, 1897, pp. 479-506. 



MARYLAND GEOLOGICAL SURVEY 01 

Maryland Geological Survey, Volume One. 

The Johns Hopkins Press, 1897. 539 pp. Plates and maps. 

Mathews, Edward B. Bibliography and Cartography of Maryland, 
including Publications relating to the Physiography, Geology and Min- 
eral Resources. 

Md. Geol. Surv., vol. i, 1897, pp. 229-401. 

1898. 
Clark, William Bullock. Administrative Eeport. 

Md. Geol. Surv., vol. ii, 1898, pp. 25-47. 

Maryland Geological Survey. Volume Two. 

The Johns Hopkins Press, 1898. 509 pp. Plates and maps. 

Mathews, Edward B. An Account of the Character and Distribu- 
tion of Maryland Building Stones, together with a History of the 
Quarrying Industry. 

Md. Geol. Surv., vol. ii, 1S98, pp. 125-245. 

The Maps and Map-Makers of Maryland. 

Ibid., pp. 337-488, plates vii-xxxii. 

Merrill, George P. The Physical, Chemical and Economic Proper- 
ties of Building Stones. 

Ibid., vol. ii, 1S9S, pp. 47-125, plates iv-vi. 

1899. 
Abbe, Cleveland, Jr. A General Eeport on the Physiography of 
Maryland. 

Md. Weather Service, vol. i, 1899, pp. 41-216, plates i-xix. 

( i.ark, William Bullock. The Eelations of Maryland Topography, 
Climate and Geology to Highway Construction. 
Md. Geol. Surv., vol. iii, 1899, pp. 47-107, plates iii-xi. 

Johnson, Arthur Newhall. The Present Condition of Maryland 
Highways. 

Ibid., pp. 1S7-263, plates xv-xxviii. 

Maryland Geological Survey. Volume Three. 

The Johns Hopkins Press, Baltimore, 1899, 461 pp. Plates and maps. 

Eeid, Harry Fielding. Qualities of good Eoad Metals, and the 
Methods of Testing them. 

Ibid., pp. 315-331, jriates xxix-xxxii. 

Sioussat, St. George Leakin. Highway Legislation in Maryland, 
and its Influence on the Economic Development of the State. 
Ibid., pp. 107-187, plates xii-xiv. 



C2 THE PHYSICAL FEATURES OF CECIL COUNTY 

1901. 

Clark, William Bullock, and Martin, Geoege Curtis. The 
Eocene Deposits of Maryland. 

Md. Geol. Surv., Eocene, 1901, pp. 19-92, plates i-ix. 

Systematic Paleontology, Mollusca. 

Ibid., pp. 122-203, plates xvii-lviii. 

Leonard, Arthur Gray. The Basic Rocks of Northeastern 
Maryland and their Relation to the Granite. 

Amer. Geol., vol. xxviii, 1901, pp. 135-176, plates xv-xix. 

Shattuck, George Burbank. The Pleistocene Problem of the 

North Atlantic Coastal Plain. 

Johns Hopkins Univ. Circ. No. 152, 1901, pp. 69-75. 
Amer. Geol., vol. xxviii, 1901, pp. 87-107. 

Maryland Geological Survey. Maryland and its Natural Be- 

sources. 

Official Publication of the Maryland Commissioners, Pan-American Expo- 
sition. Baltimore, 1901, 38 pp., map. 

Maryland Geological Survey. Maryland and its Natural Re- 
sources. 

Official Publication of the Maryland Commissioners, Inter-state 'West 
Indian Exposition, Baltimore, 1901, 38 pp., map. 

1902. 

Maryland Geological Survey. Volume Four. 

The Johns Hopkins Press, Baltimore, 1902. 

Kiis. Heinrich. Report on the Clays of Maryland. 

M«l. Geol. Surv.. vol. iv, 1902, pp. 203-505. 



THE PHYSIOGRAPHY OF CECIL COUNTY 

BY 

GEORGE BURBANK SHATTUCK 



Introductory, 



Within the past few years new methods, which have been developed 
in the study of topography, have made it possible to unravel, in a large 
measure, the past history of a region by a critical study of its physical 
features. While the older method of discussing a region by describ- 
ing in detail its various topographic aspects has by no means passed 
into disuse, yet it is employed now only to impart a mental picture 
of the region, and to prepare the way for a discussion of the geologic 
history through which the region has passed. The present top- 
ography of Cecil county is the latest chapter of a most interesting 
history, which is forever writing and never finished. Like the bits 
of glass in a kaleidoscope, the particles of sand and stone which con- 
stitute the hills and plains are constantly shifted in their position and 
arrangement, building up one combination of topographic forms in 
one geologic cycle, and another in the next. The topographic history 
of Cecil county is probably more diversified and interesting than that 
of any of the other counties which cluster about Chesapeake Bay. 
It was begun in the remote past, has continued on down the geologic 
ages to the present and is still unfinished. Many of the early portions 
of this record are unfortunately lost or obscure, but as time advanced 
the record became clearer and more continuous, until the later chap- 
ters are almost as easily read as if they had occurred yesterday. In 
treating of this subject a description of the topography of Cecil county 
will be first given, and then a discussion of the geologic events which 
have produced it. 



64 tin: physiography of cecil county 

Topographic Description. 
Cecil county is divisible into two physiographic regions; fhe Pied- 
mont Plateau and the Atlantic Coastal Plain. The former occupies 
the northern third, of the county, and the latter, the middle and 
southern thirds. The boundary between these two regions is very 
irregular and not readily described, but it is sufficiently accurate to 
state that it crosses the county from northeast to southwest in a line 
approximately coincident with the Baltimore and Ohio Railroad. 

THE ATLANTIC COASTAL PLAIN REGION. 

The Topography of the Atlantic Coastal Plain Region. — The At- 
lantic Coastal Plain is the name applied to a low and almost feature- 
less plain of varying- width, extending from Staten Island southward 
through Florida. As it passes through Maryland it varies in width 
from 16 miles in the northeastern portion of the State, to 122 miles 
in the southern portion. In general it may be understood as that 
portion of Maryland lying between the Baltimore and Ohio Railroad 
and the Atlantic Ocean. It will thus be seen that the larger part of 
Cecil county lies within this region. 

In Cecil county the Coastal Plain contains two contrasted types of 
topography. One type is a flat, low, featureless plain, and the other 
is a rolling upland attaining four times the elevation of the former, 
and resembling the topography of the Piedmont Plateau more than 
that typical of the Coastal Plain. Elk River makes the dividing- 
line between these two types of topography. On the east of it is the 
low land <d' the typical Coastal Plain, and on the west of it, are 
the rolling uplands. As this river also marks the division at the head 
of the Bay between the so-called Eastern and Western Shores, it will 
be convenient to remember that the low land east of Elk River belongs 
to the Eastern Shore of .Maryland, and is characteristic in its topo- 
graphy of that region throughout its entire extent, while the rolling 
upland of Elk Neck on the west of Elk River belongs to the vYestern 
Shore of Maryland and, in the character of the topography, is as 
typical of that region as the lowland mentioned above is of the Eastern 
SI i ore. 



MARYLAND GEOLOGICAL SURVEY 



CECIL COUNTY, PLATE IV 




MARYLAND GEOLOGICAL SURVEY 65 

The Eastern Shore district of Cecil county is triangular in shape 
with the apex directed toward the north. The base of this triangle 
at the northern bank of the Sassafras river has a width of 15 miles. 
This width rapidly diminishes north ward, and at Elkton it has de- 
creased to about two miles. Throughout this region the country is 
everywhere low and flat. It rises little, if any, above 80 feet, and 
were it not for the presence of river valleys which descend somewhat 
abruptly beneath the general level the surface of the region mighi 
be described as almost featureless. 

Notwithstanding the great monotony of this Eastern Shore district, 
a little examination reveals the fact that it is not composed of one 
plain, but of two. The more extensive level, and the one more 
readily observed, occupies the divides and the entire surface down to 
a height of 35 to 40 feet above sea-level. Tt is extensively developed 
throughout the district and attains the full width of the district at 
its southern margin. 

The second plain is developed as a narrow fringe below and about 
the margin of the first one. It seldom attains a width of over a half 
a mile and frequently is not as wide. When best developed it ex- 
tends from tide-water gradually upward to an altitude of 30 to 40 
feet, where it is separated from the upper plain by a low scarp. In 
certain localities, however, this lower plain has suffered severely from 
the erosive work of the waves and streams, and either terminates in 
a low sea-cliff or else has been entirely swept away. 

The only exception to the general level of the Eastern Shore dis- 
trict is Grays Hill, which rises to a height of 268 feet above tide, or 
about 175 feet above the surrounding plain. The mass of this hill, 
however, is composed of crystalline rocks, veneered about its flanks 
with Coastal Plain sediments, and therefor should be regarded as an 
outlier of the Piedmont Plateau rather than a portion of the Coastal 
Plain. It actually was an island rising above the level of the ocean 
when the sediments which cover the surface of the Eastern Shore 
district were deposited. 

The Western Shore district, or that portion of Cecil county lying 
between Elk River and the Baltimore and Ohio Eailroad, lies almost 



66 THE PHYSIOGRAPHY OF CECIL COTJHTY 

entirely within the peninsula of Elk Neck. Only a narrow strip lie- 
on the mainland west of it. This district is a rolling upland nearly 
four times as high as the surface of the Eastern Shore district. The 
valleys of this region, particularly those occurring on Elk Xeck, are 
much deeper and more precipitous than any occurring on the Eastern 
Shore. A careful examination has revealed the fact that the rolling 
surface of the Western Shore district is composed of four plains which 
rise, one above the other, from tide to an altitude of over 300 feet. 
The two lower ones are identical with the two plains of the Eastern 
Shore district. They occupy the same relative levels and positions, 
and almost entirely encircle the district. Above and within tl 
levels two more plains are developed occupying the higher lands. 
These extend from 90 to 180 and 180 to 311 feet respectively. They 
are not as continuous or as well developed as the two lower plain-. 
and when absent, the hills are composed of the underlying materials 
on which they formerly rested. A range of high hills extends down 
the centre of Elk Neck, attaining an altitude of 300 feet among the 
Hog Hills, 311 feet at Black Hill, 306 feet at Bull Mountain, and 
240 feet at Maulden Mountain. On the mainland, the highest 
altitude attained in this district is 420 feet at Eoys Hills. This marks 
also the highest point in the entire Coastal Plain region of Cecil 
county. 

The Drainage of the Atlantic Coastal Plain Region. — The drain- 
age of the Atlantic Coastal Plain region is divisible into two great 
types of rivers; the estuaries and the creeks. The estuaries are 
branches of Chesapeake Bay, which extend well back into the sur- 
rounding country and ebb and flow with the tide. They are in reality 
valleys of ancient rivers, which have been depressed to such an extent 
as to be submerged below the surface of Chesapeake Bay and to per- 
mit the encroachment of its waters. In all there are ten of these 
estuaries which either lie wholly within or set their courses across this 
< <>;i*tal Plain region. They are the Susquehanna river, Furnace 
Creek, Northeast River, Elk River, Back River, Bohemia River, Cabin 
John Creek, Pierce Greek, Pond Creek, and the Sassafras river and 
its tributaries. The Sassafras river, which marks the southern border 



MARYLAND GEOLOGICAL SURVEY 67 

of the county, is an estuary for almost its entire course. It extends 
inland due east from Grove Point and is navigable for 9 miles, as 
far as Georgetown. Elk River, the largest of the estuaries, extends 
in a northeast direction from the extremity of Elk Neck at Turkey 
Point to Elkton, a distance of 15 miles, and is navigable throughout 
its entire extent. Toward the east it sends out two important rami- 
fications. Bohemia River is an estuary for 7 miles. Back Creek, 
which crosses the county as a navigable waterway, connects with the 
Delaware river by means of the Chesapeake and Delaware Canal. 
On the western side of Elk Neck, Northeast River extends up into 
the land as an estuary for a distance of about 5 miles, and Furnace 
Creek, two miles to the west, penetrates inland for a distance 
of about 1-| miles. All of these estuaries lie wholly within the 
Coastal Plain region. Only one estuary crosses the region, that 
of the Susquehanna river, the lower portion of which is submerged 
and navigable some five miles above its mouth to Port Deposit. 

The other category of drainage ways, or the creeks, includes flowing 
streams which carry the water from the surface to Chesapeake Bay 
and its estuaries. These creeks are prevailingly short, the largest 
not much exceeding 5 miles in length. Their drainage basins are 
correspondingly restricted, and because of this fact, the streams 
partake largely of the character of mountain torrents; flow only 
(hiring the wet season of the year or immediately after a storm, and 
frequently become dry at least throughout a great portion of their 
courses during the dry weather. An exception to this general rule is 
found in the northern margin of the Atlantic Coastal Plain district 
where streams, such as the Little Elk, Northeast Creek and Prin- 
cipio Creek, which rise within the Piedmont Plateau and drain from 
the more extensive basins, are obliged to cross the Coastal Plain to 
( hesapeake Bay. Within the Eastern Shore district, the creeks have 
cut deep, narrow valleys beneath the surrounding surface, as time 
has not been sufficient since the emergence of the land above the ocean 
to permit the streams to widen extensively their basins. The creeks 
which drain the peninsula of Elk Neck differ from those over the rest 
of the Coastal Plain streams of Cecil county, in that they rise on 



68 I III-: PHYSIOGRAPHY OF CECIL COUNTY 

higher land: flow with shorter and more direct courses to the Bay, 
and have cut deeper and narrower valley-. 

All over the Atlantic ( loastal Plain region the creeks are constantly 
bearing great loads of sediment from their easily eroded basins to 
Chesapeake Bay. As by far the larger number of these creeks have 
been converted to estuaries at their mouths, the tendency is to deposit 
their loads of debris as soon as the quieter waters of their lower 
courses are reached. The result is that their months are rapidly 
rilling up, and as a direct result of this, the little estuaries are being 
constantly narrowed and shortened, and streams which a few years 
ago were navigable to a considerable distance from their mouths are 
now converted into shallow swamps and marshes. What has just been 
said regarding the creeks is also true regarding the larger estuaries. 
These are all fed by numerous creeks throughout their courses and 
are constantly receiving through them large supplies of debris from 
the surrounding country. As a result of this tribute, the upper 
courses of the estuaries have been converted into impenetrable 
marshes, and the deltas thus forming are rapidly advancing down the 
stream. The most conspicuous instance of this stream-filling i< 
found at the head of Elk River estuary, where the upper part of the 
estuary has been converted into a delta some two miles or more in 
extent; leaving the town of Elkton far inland and connected with the 
waters of the estuary by only a narrow meandering stream, navigable 
with great difficulty. 

The Structure of the Atlantic Coastal Plain Region. — The materials 
of which this region is built up are composed of clay, loam, sands, 
gravel and boulders. These deposits are loose and unconsolidated, 
with the exception of crusts of ironstone, which are locally developed, 
and thin beds of conglomerates which cap certain high hills on Elk 
Neck and the mainland. Although the materials which have built 
up the Atlantic Coastal Plain have been deposited at various times, 
and belong to a large number of different geological horizons, -till 
they all lie either horizontal, or nearly so. Those which have been 
tilted most, seldom exceed a dip of I" Eeel to the mile. The structure 
of the region, therefore, has nol seriously influenced the drainage. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE V. 




FIG. l.-TOPOGRAPHY OF ELK NECK, CECIL COUNTY. 




Fig. 2.— TURKEY POINT, FROM MAULDEN MOUNTAIN. 



VIEWS OF CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 09 

and the rivers flow from its surface as if they were flowing from a 
country composed of unconsolidated deposits of clays, sands and 
gravel horizontally bedded throughout. 

THE PIEDMONT PLATEAU REGION. 

The Topography of the Piedmont Plateau Region. — The Piedmont 
Plateau is the name applied to a rolling and picturesque upland, 
occupying the region between the Atlantic Coastal Plain on the east, 
and the eastern margin of the Appalachian Mountain System on the 
west, and extending from New York to the middle of Alabama. As 
it passes through Maryland it varies in width from 85 miles in the 
northeastern portion of the State to 37 miles in the southern portion. 
In general it may be understood as that portion of the State of Mary- 
land lying between the Baltimore and Ohio Railroad on the east, and 
the Blue Ptidge and Catoctin Mountain on the west. It will thus be 
seen that the northern third of Cecil county lies within the Piedmont 
Plateau region. 

Although the Baltimore and Ohio Railroad may be regarded 
roughly as the boundary between the Piedmont Plateau and the 
Atlantic Coastal Plain, yet the contact between them is by no means 
as sharp as the definition would seem to indicate. On the one hand, 
the deposits belonging to the Coastal Plain extend well up on the 
surface of the Piedmont Plateau, in some instances as much as 5 
miles north of the Baltimore and Ohio Railroad, and on the other 
hand, the rocks of the Piedmont Plateau are exposed in the beds 
of creeks well within the Coastal Plain and may reach as much as 
one and a half to two and a half, or even three miles south of the 
same railroad. The surface of the Piedmont Plateau is gently roll- 
ing, except where it is crossed by the more important drainage lines, 
such for instance as the Big Elk, Little Elk, Principio, Octoraro, 
Conowingo creeks, and the Susquehanna river. Wherever these 
streams cross the region they have cut deep and usually narrow 
gorges imparting a rugged and picturesque beauty, to otherwise soft- 
ened topography. Leaving the relative elevation aside for a moment, 
there is between the general topography of the Piedmont region and 



70 



THE PHYSIOGRAPHY OF CECIL COUNT Y 



the Eastern Shore division of the Coastal Plain a great contrast, while 
between it and the Western Shore division of the Coastal Plain, the 
difference is less marked, and the one region merges over into the 
other so imperceptibly that the point of change must be sought not 
so much, if at all, in a study of the topographic features, as in an 
examination of the deposits. In regard to the elevations of the 
Piedmont Plateau region, it may be said that its average height is 
considerably above that of the Western Shore division of the Coastal 
Plain, although its maximum height exceeds it only by about 100 
feet. The greatest height of the Coastal Plain, as pointed out above, 
is about 440 feet, while the greatest height of the Piedmont Plateau 
within the county is about 540' feet, near Rock Springs. As these two 
localities are separated by about 12 miles, and the intervening and 
neighboring regions rise seldom above 400 to 440 feet, it will be 
readily seen that the difference of the highest portions of the Coastal 
Plain and the highest point of the Piedmont Plateau are not appre- 
ciable to the eye. 

The Drainage of the Piedmont Plateau Region. — The rivers of the 
Piedmont Plateau region may be grouped into five main streams. 
These are, beginning on the east, the Big and Little Elk creeks; the 
.Northeast River, Principle Creek and the Susquehanna River. The 
latter in turn receives two tributaries, the Conowingo and Octoraro, 
which enter the county from Pennsylvania. Besides these principal 
streams, there are a large number of minor ones which carry off the 
surface waters by short courses to the Susquehanna or to Chesapeake 
Bay. These streams are all characterized by a common feature, 
which is developed in proportion to the capacity of the stream. The 
characteristic which they hold in common is the deep and usually 
narrow rock-bound gorges in which they flow. The bed of the 
Elk River lies 100 feet or more below the surface of the surrounding 
country, and the gorges of the Susquehanna and its tributaries exceed 
this depth. These gorges, however, are usually confined to the main 
body of the stream. The headwaters of tributaries flow across the 
country in wide .-hallow valleys, and only gradually sink gorges as 
they approach the main trunk stream-. 



MARYLAND GEOLOGICAL SURVEY < 1 

The Structure of the Piedmont Plateau Region.— The materials of 
the Piedmont region consist of crystalline rocks of very great age. 
These have been formed at various times, and under very different 
conditions. The older rocks have been folded, rent asunder, and 
intruded by younger rocks, which in their turn have been subjected 
to the same 'processes until the region exhibits a most complicated 
interlocking of metamorphic and eruptive rocks. 

Topographic History. 
A careful study of these topographic features and of the deposits 
which composed them, reveal some of the incidents which have given 
rise to the present relief. An outline of the topographic history will 
now be given, under the following seven stages, beginning with the 
oldest : 

1. The Crystalline Kock Forming Stage. 

2. The Schooley Peneplain Stage. 

3. The Lafayette Stage. 

4. The Sunderland Stage. 

5. The Wicomico Stage. 

6. The Talbot Stage. 

7. The Recent Stage. 

THE CRYSTALLINE ROCK FORMING STAGE. 

With the exception of remnants of Coastal Plain sediments, which 
•are scattered along the southern border of the Piedmont Plateau, 
the rocks of the latter are either eruptive or metamorphic. Research 
has shown that the Piedmont Plateau was part of an ancient uplift, 
possibly a low mountain system, which was developed as a long, 
narrow' peninsula or island, extending from Canada to Alabama, and 
separating the Atlantic Ocean on the east from a great Interior Sea 
which covered the central part of North America on the west. This 
land mass ante-dated the Appalachian Mountain system, and the 
materials which were stripped from its surface and carried out west- 
ward into the Interior Sea, contributed in a large measure to the 
building up of deposits which were afterward raised to form the 



I '1 THE PHYSIOGRAPHY OF CECIL COUNTY 

Appalachian Mountains. The extent of this ancient land mass can- 
not be accurately determined, hut it seems certain that only a portion 
of it is represented by the Piedmont Plateau, and that another large 
part has disappeared and is now buried beneath Coastal Plain sedi- 
ments or submerged beneath the waters of the Atlantic Ocean. 

A portion of the Piedmont rocks which are now crystalline, were 
not always so, but were in the form of sediments deposited by an 
ancienl sea. On being folded up into a mountain system, they were 
not only transformed from clastic to metamorphic rocks, but were 
also injected with a quantity of eruptive rocks, introduced from lower 
regions. These rocks, which were first situated deep within the 
earth's crust, have been brought to the surface by the erosion of the 
cover which formerly overlaid them, and now lie exposed in the 
Piedmont hills. 

THE SCHOOLEY T PENEPLAIN STAGE. 

At the close of the Paleozoic period, the sediments which had been 
accumulated in the Interior Sea to the west of the Piedmont Plateau, 
were raised into the Appalachian Mountains. It is not known that 
the Piedmont Plateau shared in this movement, but it is certain that it 
suffered greatly during the erosion interval which followed. This 
period of erosion, which took place in Mesozoic time, was of great 
duration and extent. When it began, the Appalachian Mountains 
were probably as high, if not higher, than they are today; when it 
came to a close, the mountains had almost entirely vanished, and in 
their place there was a low and nearly featureless plain which ex- 
tended out across the Piedmont Plateau to the Atlantic Ocean. This 
peneplain, which was almost co-extensive with the Appalachian uplift, 
is known in Maryland and the neighboring regions as the Schooley 
peneplain. Before this erosion period came to a close, however, the 
eastern margin of the Piedmont Plateau seems to have been depressed 
below tide-level, and buried under a load of Cretaceous sediments; 
thus while erosion was completing the plaination of the interior por- 
tion of the Schooley peneplain, deposition was taking place along it- 
eastern border. The deposition of these sediments was not contin- 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE VI. 




v%%. 






*&3 



Fig. 1.— A YOUXG VALLEY IN UNCONSOLIDATED COASTAL PLAIN DEPOSITS. 




t 



i 



FIG. 2.— WAVE-CUT CLIFF ON WEST SHORE OF ELK NECK. 
VIEWS OF CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 73 

nous, but was interrupted by numerous oscillations in level, during 
which the region was brought above the sea and suffered erosion, 
only to be depressed again and re-loaded. These changes in the atti- 
tude of the land in relation to sea-level have been recorded as uncon- 
formities in the deposits, but they have left no noticeable record in 
the topography, and their discussion is consequently deferred to a 
later chapter. 

At the close of this period of sedimentation there was a general 
uplift of the region, which brought Cecil county once more above the 
sea. After this there followed a long period of erosion, which was 
finally brought to a close by the entire county again sinking beneath 
the ocean. This subsidence ushered in the Lafayette stage. 

THE LAFAYETTE STAGE. 

The subsidence which marked the beginning of the Lafayette stage 
effected the entire Atlantic Coastal Plain from New Jersey south- 
ward. In the northern portion of the area it is impossible to deter- 
mine how far inland the waters of the Atlantic Ocean advanced, but 
there is no doubt that Cecil county was entirely submerged and, at 
the time of maximum depression, the waves of the Atlantic may have 
washed the eastern base of the Blue Ridge. The date of this subsi- 
dence has been doubtfully referred to the Pliocene period. 

While Cecil county was thus engulfed it received a load of deposits 
which are now known as the Lafayette formation. 

At the close of the Lafayette depression Cecil county was again 
lifted above the surface of the ocean, and probably to a much greater 
extent than now. Chesapeake Bay at that time did not exist, but 
its trough was occupied by the lower courses of the Susquehanna 
river, which received as tributaries from the surrounding country 
the streams which are now estuaries. Just how long the land re- 
mained in this position it is impossible to say, but sufficient time 
elapsed to permit the erosion of a large amount of the sediments 
which had been brought up out of the Lafayette Sea. The Lafayette 
formation was in a large measure stripped off from the Piedmont 
Plateau region of Cecil county, as well as from the Eastern Shore 



74 



THE PHYSIOGRAPHY OF CECIL COUNTY 



and Elk Xeck, thus bringing once more to the surface the older 
underlying rocks. 

THE SUNDERLAND STAGE. 

This period of emergence and erosion was brought to a close by a 
partial subsidence of Cecil county. This subsidence may have been, 




Fig. 1.— Showing position of Sunderland shore-line. 

and probably was, accompanied by a slight tilting of the region to 
the southeast. As the land went down the sea advanced both from 
the Atlantic side and up the sinking valley of the Susquehanna river, 
until it came to a standstill somewhere near the present location of 
the I laltimore and Ohio Eailroad. "When the sea had thus encroached 
on the land the topography of Cecil county was very different from 
what it is to-day. The accompanying diagram (Fig. 1) gives an 



MARYLAND GEOLOGICAL SURVEY I O 

approximate idea of the appearance of the comity during Sunderland 
time. A glance at this chart suffices to show that all of the Eastern 
Shore and much of the region between the Susquehanna and North- 
east rivers was submerged, while the peninsula of Elk Neck was 
greatly diminished in width and its southern extremity, at least, con- 
verted into a chain of islands. Grays Hill also stood up as an island, 
a few miles out in the ocean from the mainland. As the Sunderland 
Sea thus overspread the larger part of the county and the waves rolled 
unhindered from the Atlantic Ocean, they broke heavily against the 
shore and cut a well-pronounced sea-cliff all along their margins, 
precisely as the waves are now doing at intervals along the Atlantic 
coast. The currents which swept along the shores of the Sunderland 
Sea picked up the debris which was surrendered to them from the 
land, and with it built up spits and bars along the shore. 

These events were brought to a close by another uplift of the land. 
That portion which had previously been covered by the ocean was 
now transformed into land, and the rivers which sprang rapidly into 
existence began again to carry out to the sea the materials which had 
so recently been deposited. It is difficult to say how long this period 
of emergence lasted, but it probably was of sufficient duration to 
permit a partial uncovering of the older rocks by the erosion of the 
deposits laid down by the Sunderland Sea. 

THE WICOMICO STAGE. 

I 

After the erosion of the Sunderland deposits had continued for 
some time, the region began again to sink and the sea to encroach 
on the land until the Atlantic Ocean had advanced nearly to the 
position which it had previously occupied in the Sunderland stage. 

The accompanying diagram (Fig. 2) will suffice to illustrate the 
position of the shore-line at this time. The full line indicates the 
approximate position of the Wicomico shore-line, while the broken 
line indicates that of the present shore-line. It will be readily under- 
stood from this diagram that while the Wicomico submergence was 
of the same character as the Sunderland, yet it was not quite so 
extensive, and more of Cecil county remained above the ocean than 



76 



THE PHYSIOGRAPHY OF CECIL COUNTY 



in the former period. Although the land did not remain indefinitely 
in this position, still time enough elapsed to permit the waves to again 
cut well-pronounced sea-cliffs along most of the shore-line. 

Again the sea and the land changed their relative position and 
( Ceil county emerged from beneath the ocean. The rivers once 




Fig. '2. — Showing position of Wicomico shore-line. 

more began to return to the sea the material which had been so lately 
deposited by it, and a large quantity of the sediments of the "Wicomico 
Sea were stripped from the surface of the county and carried out to 
deep water. 

THE TALBOT STAGE. 

Once more the sea advanced, but this time to a very much less 
extent than it had in the two previous stages. As the land gradu- 



MARYLAND GEOLOGICAL SURVEY 



77 



ally sank beneath the encroaching ocean, the waters worked their 
way up the sinking valley of the Susquehanna and its tributaries, 
converting them into estuaries, until it had arrived approximately 
at the position indicated in the accompanying diagram (Fig. 3). 




Fig. 3. — Showing position of Talbot shore-line. 

Here it came to a standstill and remained in that position long 
enough to cut a third series of sea-cliffs in the more exposed head- 
lands. It will be seen that the aspect of Cecil county during the 
Talbot stage was not very different from what it is today. It was 
simply an enlargement of the Chesapeake Bay and its system of 
estuaries. It was at this time that the lower terrace now extending 
from tide to a height of 40 or 45 feet was deposited. 



78 THE PHYSIOGRAPHY OF CECIL COUNTY 

THE RECENT STAGE. 

The time which elapsed during the deposition of the Talbot forma- 
tion was probably much shorter than that occupied by any previous 
epoch. The land again rose to a position higher than that occupied 
today, ami Chesapeake Bay and its system of estuaries shrank con- 
siderably beneath their present dimensions. This stage is illustrated 
approximately by the present shore-line. Since that time the region 
has <aice more started in a downward direction, and little by little 
i- sinking beneath the waters of the Atlantic Ocean and of Chesa- 
peake Bay. The movement is exceedingly slow and only appreciable 
to one who is trained to compare phenomena which are years in 
their execution. Cecil county is, therefore, at the present time under- 
going another period of partial subsidence and deposition. 

The Origin of the Streams of the Piedmont Plateau. 

Of the streams which cross the Piedmont Plateau of Cecil county, 
Conowingo, Octoraro, Principio, Northeast and Big and Little Elk 
creeks are the most important. These streams have three important 
characteristics in common: first, they flow in deep, narrow gorges 
throughout the lower portions of their courses, while their head 
waters descend little, if any, below the general level of the country. 
This feature is best seen in Principio, Northeast and Big and Little 
Klk creeks. These three streams are confined almost entirely to 
the Piedmont Plateau of Cecil county, and the change from a bed 
at the bottom of a deep gorge to one lying on the flat surface takes 
place within a few miles. The case of Conowingo and Octoraro 
creeks is somewhat different as these waters head well back in Penn- 
sylvania. Their upper courses are not shown on the atlas of Cecil 
county, but if the streams were followed backward far enough, they 
too, would be seen to rise gradually from the bottoms oJ gorges to 
thi surface of the country. 

The second feature which the streams hold in common is that they 
cross the Piedmont Plateau, not in short, direct courses, but in long, 
winding channels. This meandering feature is best developed in 
Octoraro Creek, although possessed to a certain extent by all the 



MARYLAND GEOLOGICAL SURVEY 79 

other streams; thus, Conowingo Creek develops two ox-bows in its 
course just before it passes over into Cecil county from Pennsylvania, 
and Principio, Northeast, Little and Big Elk creeks all exhibit mean- 
dering courses, particularly toward their headwaters. 

The third feature is that none of the streams have confined their 
courses to any one sort of rock, but pass abruptly from one kind to 
another, and back again, and run indiscriminately through rocks of 
varying hardness and solubility. Octoraro Creek shows this feature 
also most strikingly. The wavering course of this channel runs 
abruptly off of one kind of rock to cut an ox-bow in another, and 
suddenly returns to the first, only to leave it again a few miles further 
down. Thus the stream enters the State from Pennsylvania, eroding 
on a serpentine rock; this it leaves abruptly to cut through a dike 
of pegmatite, then flows athwart a mass of hypersthene-gabbro avoid- 
ing two other pegmatite dikes. After leaving this rock, it cuts 
abruptly through a. mass of meta-gabbro and into a formation of 
granite-gneiss. In this rock it erodes an ox-bow, then turns and 
runs suddenly into the meta-gabbro once more. After flowing along 
the border between the meta-gabbro and granite-gneiss for about half 
a mile the stream re-enters the mass of the latter and remains in it 
until it reaches the Susquehanna river. The crystalline rocks of 
Cecil county are not strikingly different in their powers of with- 
standing erosion, and the anomaly of a stream crossing from one sort 
of rock to another and back again is not as well brought out in this 
county as further south, where streams along the Piedmont Plateau 
run abruptly from very soft to very hard rocks and back again with 
utter disregard of the great differences in the varying powers of the 
rocks to withstand erosion. 

It has been demonstrated by countless field observations that nor- 
mal streams, when they have a steep grade and rapid current, tend 
not only to flow in direct courses, but also to avoid the harder rocks, 
and to establish their channels in the softer ones, thus moving along 
the lines of least resistance. The streams of the Piedmont Plateau 
are therefore not normal, but the contrary, and as they all possess 
these abnormal features, it would seem to point to some cause which 



80 THE PHYSIOGRAPHY OF CECIL COUNTY 

has acted on all alike, and modified all the drainage systems in a 
similar manner. The causes which have produced this peculiar drain- 
age are to be sought for in the past history of the region. It has 
already been shown that the changes through which the Piedmont 
Plateau has passed are many and complex. The region which was at 
one period, above the ocean and undergoing erosion, was at another 
time below and receiving sediments, only to be again raised and 
denuded. The amount of erosion which the region underwent dur- 
ing any one period of uplift depended on the duration of that period. 
If the period was short, the erosion would be slight; if long, the 
erosion would be correspondingly great. It is known that the 
Piedmont Plateau did .for a long time stand above sea-level, and that 
during that period it suffered a vast amount of erosion. This erosion 
interval probably began in Paleozoic time and extended to the 
Jurassic or Lower Cretaceous. Throughout this great period, em- 
bracing, doubtless many millions of years, the Piedmont Plateau is 
believed to have been above sea-level ; if at any time it was submerged, 
no record of such submergence now remains. During this inter- 
val, the Appalachian Mountains and the highlands which previously 
existed on the site of the present Coastal Plain were gradually cut 
down to the Schooley peneplain. Such a transformation required a 
vast amount of time for its accomplishment; but when it was com- 
pleted, the rivers which brought about the change had fixed their 
courses in the softer rocks and had avoided the more obdurate ones. 
During Cretaceous time, or probably earlier, the eastern portion of 
the Schooley peneplain sank beneath the Atlantic, and was buried 
under n heavy load of sediments; at a later period, the region was re- 
elevated and appeared once more above the water iadened with these 
deposits. On this new land surface, streams at once began to How 
;iik1 established their courses in harmony with the conditions there 
presented. As the old valleys of the Schooley peneplain had been 
filled in and obliterated, the channels now cut out and occupied 
by the new system of rivers were entirely independent of those 
produced by any previous streams. They were uninfluenced by 
the buried topography and pursued their courses on the slowly 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE VII. 




FIG. 1.— SUSQUEHANNA FROM WILDCAT POINT, SHOWING SIDE VALLEYS. 




FlG. 2.— VIEW OF ROCKY SIDE STREAMS NEAR BALD FRIAR. 



VIEWS OF CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 



81 



emerging sea-bottom as on a new land surface; gradually they sank 
their valleys deeper and deeper in the cover of soft sediments, and 
finally, one by one, reached the underlying buried crystalline rocks 
(Fig. 4). The structure of these rocks on which the streams now 
began to flow was extremely complex and entirely different from 
that of the formations through which they had just cut their valleys. 
Thus, on reaching the buried rocks, the drainage was immediately 




Fig. 4. — Diagram showing origin of superimposed river. 



out of adjustment with the conditions there encountered. Neverthe- 
less, the rivers, unable to alter their courses, continued to sink their 
channels with the same circuitous courses which the} 7 had developed 
when meandering across the low, featureless surface of the newly- 
raised ocean-bottom. Thus it came about that these streams, cutting 
on whatever rocks they happened to uncover, would at one time erode 
a hard and at another time a softer rock, as each chanced to appear in 
their beds. In this way a drainage pattern which had been developed 
on one kind of deposits, in harmony with the conditions which there 
existed, became fixed in the underlying crystalline rocks, although 

out of adjustment with the conditions which were there found. Thus 
(i 



82 THE PHYSIOGRAPHY OF CECIL COUNTY 

is explained the meandering - courses of the Piedmont rivers of Cecil 
county. Such streams are said to he superimposed. 

Much discussion has arisen regarding the particular sedimentary 
beds through which this superposition of the rivers took place. At 
this time only fragments of the Coastal Plain sediments remain on 
the surface of the Piedmont Plateau. The rivers which were super- 
imposed through the cover of unconsolidated deposits have succeeded 
in removing almost all of the materials through which their sinuous 
courses were set. This superposition may have been made through 
the beds of the Potomac group, or through those belonging to the 
Upper Cretaceous, or possibly through the Lafayette. The most that 
can be said is that it took place through Coastal Plain deposits, and 
it is probable that the Lafayette formation had a good deal to do 
with fixing the courses of the present streams. 

Since the streams have established their courses on the rediscovered 
surface of the Piedmont Plateau, the region as a whole has undergone 
an uplift. This elevation has stimulated the erosive work of the 
streams. As yet, however, only the lower courses of the streams 
have responded to this rejuvenating influence. These are the por- 
tions which would naturally profit first by the uplift, and it is along 
their lower courses that the streams have deepened their channels and 
flow in gorges, while toward their headwaters, they emerge from their 
chasms and flow along the surface of the plateau. 



THE GEOLOGY OF THE CRYSTALLINE ROCKS 
OF CECIL COUNTY 



BY 

BASCOM 



Introductory. 

The discussion of the succeeding pages will be confined to the belt 
of metamorphic and igneous formations which appear at the surface 
in the northern and northwestern half of Cecil county. South of a 
line extending from Perry ville to Iron Hill Station they are com- 
pletely concealed, with the exception of a few scattered outliers, by 
the gravels, clays and sands of the Cretaceous, Tertiary and Pleis- 
tocene. North of this line there are light coverings of Potomac and 
Columbia gravel, which exhibit very irregular boundaries upon the 
crystallines and possess numerous inliers. 

The area! distribution, stratigraphy, structural relations, age and 
petrography of the formations of this district will be the special 
subjects of the following pages. 

The physiography and soils of the region are fully dealt with else- 
where and will be only incidentally considered here. 

The bibliography of this belt is included in the general bibliography 
of Cecil county (pp. 49-62) and a summary of previous investigations 
is given elsewhere (pp. 39-41). The most detailed investigations, 
and the only petrographic studies, of the crystallines are represented 
by A. G. Leonard's Dissertation 1 " The Basic Rocks of Northeastern 
Maryland and their Relation to the Granite," and by G. P. Grims- 
ley's Dissertation 2 " The Granites of Cecil County " in Northeastern 
Maryland, which were prepared at the Johns Hopkins University. 

1 Amer. GeoL, vol. xxviii, 1901, pp. 135-176, plates xv-xix. 

* Journ. Cincinnati So.Q. Nat. Hist., vol. xvii, 1894, pp. 56-G7, 87-114. 



84 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

The material collected by these geologists and by Dr. Edward B. 
Mathews has been placed at the disposal of the writer, who, while 
differing in some particulars from their conclusions, has found their 
results of great assistance in reducing the labor of investigation. 

Geographic and Geologic Relations. 

The crystallines of Cecil county are part of a broad belt of meta- 
morphosed sedimentary material and intrusive igneous formations, 
which extends along the Atlantic coast from Alabama to Maine and 
northward. 

This belt, trending northeast and southwest, forms the plateau 
region on the eastern foot of the Appalachian district, 

In New England the belt is well developed. In New Jersey the 
formations are largely concealed beneath a covering of Triassic de- 
posits. In Pennsylvania and Maryland the materials of this belt are 
again well exposed through the removal of a large part of this 
covering. 

The determination of the age, origin and structural relations of 
these formations has long been a serious problem to geologists. 

In New England detailed investigation by Pumpelly, Emerson, 
Dale, Wolff and Hobbs has resulted in the determination of Cam- 
brian, Lower and Upper Silurian series of quartzites, marbles, schists 
and gneisses, resting upon a protruding pre-Cambrian gneiss. 

In Pennsylvania Cambrian and Silurian quartzites and crystal- 
line limestones have been determined in the western half of this belt, 
while the structure and age of the gneisses of the eastern half arc 
still problematical. 

A natural division is manifest in the Piedmont belt of Maryland, 
as in Pennsylvania. The western half of the belt contains formations 
which are plainly of sedimentary origin, though nonfossiliferous and 
" semicrystalline," and have been placed (provisionally) in the Cam- 
brian-Silurian periods. 

The formations of the eastern division present more obscure 
problems in origin and age. They have undergone such complete 
metamorphism as to obscure or obliterate all evidence of origin or of 



MARYLAND GEOLOGICAL SURVEY 85 

original structural planes. They have been considered pre-Cambrian 
(Algonkian and Archaean), with some infolded Cambrian-Silurian 
quartzites, marbles and phyllites. 

It is of this eastern division of the Piedmont belt of Maryland 
that the crystallines of Cecil county are a part. Though less than 
one-sixth of the Maryland extension of the belt, the Cecil county 
crystallines include a representative series of the formations of the 
belt. 

These holocrvstalline metamorphic rocks enter Maryland from the 
southeastern corner of Pennsylvania and cross Cecil county from 
northeast to southwest, where they pass into Harford county. Their 
southeastern border is buried beneath the unconsolidated materials 
of the Coastal Plain. 

Like all of eastern Maryland, Cecil county shows a striking topo- 
graphic division into a southeastern lowlying coastal plain district 
and a northwestern rugged plateau region. The unconsolidated for- 
mations: clay, sand and gravel characterize the former district, while 
the hard rocks are confined to the plateau. Thus the southern 
boundary of the crystalline formations of Cecil county is practically 
coincident with the chief physiographic division of the county. 
The Baltimore and Ohio Railroad skirts the southeastern limits of 
the plateau and of the crystallines. The state limits toward Penn- 
sylvania and Delaware, and the Susquehanna river furnish the north- 
ern, eastern and southwestern boundaries, respectively, of the trape- 
zium which encloses at once the plateau region and the Piedmont 
belt of Cecil county. 

The marked physiographic features of the county are in close 
correspondence with the geologic features, and the geologic and 
physiographic districts are coincident. 

The plateau slopes gently to the southeast. Its highest elevation, 
in the neighborhood of Rock Springs, is about 550 feet above tide. 
The western portion of the plateau is drained and deeply caiwed by 
the Susquehanna river and two chief tributaries, the Octoraro and 
Conowingo creeks. Basin Run, Rock Run and Happy Valley Branch 
are the lesser tributaries. The Susquehanna, flowing transverse to 



86 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

the strike of the hard rocks and with the cleavage dip, has cut its 
gorge with some difficulty. Navigation above Port Deposit, except 
by small craft, is rendered impossible l>y the innumerable island-. 
projecting ridges of rock and submerged ledges which interrupt the 
channel of the river and give rise to frequent rapids. 

It is to this feature that the stream owes its name, which is said to 
signify in the aboriginal tongue " river of islands." 

Many of these island- were the former secure and picturesque 
homos of the Sn^jueliannocks — or " River Islanders" and are now 
a rich collecting ground for aboriginal domestic utensils, stone axes, 
spearheads and other implements of war. 

The gorge of the Susquehanna in Cecil county is some 400 to 450 
feet in depth. The first 200 feet rise abruptly and give a consider- 
able grade to the tributaries. The walls of the gorge approach close 
to the river bed, except at the entrance of the larger tributary streams, 
where the deposits of the entering streams have formed low alluvial 
plains some three-eighths of a mile in width. 

One of the principal towns of the county, Port Deposit, occupies 
such a plain, which has been artificially widened. This situation, 
three miles above the mouth of the Susquehanna, at the head of navi- 
gation, possessing good waterway and railway connections with Phila- 
delphia, Baltimore and Harrisburg, has acted most favorably on the 
chief industry of the town; the quarrying and shipping of building- 
stone. The high bluffs behind the town offer a picturesque and 
healthful location for the rapidly developing Jacob Tome Institute. 

The only two tributaries of considerable size, the Conowingo 
and the Octoraro, have brought their lower courses, which are con- 
tained in Cecil county, almost to base-level. The incised meanders of 
the latter creek indicate that this has been achieved more than once. 
The carving of these two streams and of the Susquehanna has given 
a rugged and picturesque character to the northwestern part of Cecil 
county, which it does not elsewhere possess. Bold bluffs, wooded 
bills, the flash of winding streams over rocky beds, compose a land- 
scape which is a constant yet ever varying source of refreshment to 
the eye. 



MARYLAND GEOLOGICAL SURVEY 87 

The eastern portion of the plateau is drained by Principio Creek, 
Stony Run, Northeast and Little Northeast creeks, Little Elk and 
Big Elk creeks. These streams empty into estuaries which represent 
their submerged lower courses. At their mouths, which are also the 
heads of navigation, and at the mouth of the Susquehanna, are situ- 
ated the only considerable towns, other than Port Deposit and Rising 
Sun, of this district. 

Elkton on Big Elk Creek, Northeast on Northeast Creek, Principio 
Furnace on Principio Creek, and Perryville on the Susquehanna, 
all possess good waterway and railway facilities. 

The more easterly of the streams have a fall within the county of 
about 200 feet, and the more westerly of nearly 400 feet. They are 
simple streams, consequent upon the elevation of the plateau, and 
their volume is not sufficient for rapid erosion. 

The eastern and central portions of the plateau are not deeply dis- 
sected. Possessing a nearly uniform level, in its featureless aspect, 
this region presents a strong contrast to the western portion of the 
county. The soil is a clay loam and the land has no superior in the 
county for agricultural purposes. Rich fields of grain, prosperous 
farms, and substantial farm buildings attest the productiveness of 
the soil and produce a not unattractive landscape. 

There are no considerable towns in this central plateau region. 

Rising Sun, the largest town, does not reach a population of 400 
(384). It is the center of this agricultural district and possesses 
good railway facilities. The rock lies deeply buried beneath the 
clay loam and almost eludes the geologist. The only stone turned 
up by the plow is vein-quartz or flint, a material abundant and 
universal in distribution. This district presents greater difficulties 
in areal mapping than does the more deeply incised western area. 

Areal Distribution and Character of the Crystalline 
Formations. 1 
Six groups, with several subordinate types of rocks, are embraced 
in the belt of crystallines of Cecil county. In general they form 

'For an explanation of the more technical terms used see the glossary at the end 
of the chapter. 



88 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

successive belts, trending alike northeast-southwest across the plateau. 
Their areal distribution will be outlined briefly and can be readily 
understood with the assistance of the accompanying geological map. 

mica-gneiss. 

Among the crystalline formations of the county there is but one 
that is of sedimentary origin. This origin is greatly obscured by 
complete metamorphism. The rock is a very schistose gneiss, vary- 
ing from a somewhat coarsely crystalline muscovite-biotite-gneiss to 
a finer grained muscovite-chlorite-gneiss, or to a chloritic quartzite. 
It may be conglomeratic, or it may show distinctly marked quartzose, 
micaceous, and gneissic beds. It is best exposed on the Susquehanna 
river from Bald Friar Station northwest to the State line. It appears 
here in a succession of bold cliffs, 100 to 150 feet in height. The 
cliffs approach the water's edge on both sides of the river and give 
rise to the wildest scenery of the county. 

At Wildcat Point a cleft in the rock, forming a passage some 50 
feet in depth, is known as Wildcat cave. At this locality the strike 
of the formation is N ± 60° E. 

At Bald Friar the strike is JST 75° E. Elsewhere the strike lies 
between 35° and 55° east of north. 

The stratification when shown is uniformly inclined to the south- 
east and varies in dip from 30° to 80°. 

The areal distribution of the gneiss in the northwestern corner of 
Cecil county is limited to an equilateral triangular area, whose sides 
are approximately two and one-half miles in length. 

It is cut off on the southeast by intrusive igneous material, and 
encloses a considerable body of the same character. The gneiss 
passes over the state boundary into Pennsylvania, where it is an 
extended and important formation. It is areally continuous to 
the east in Lancaster and Chester counties in Pennsylvania, but in 
( ceil county the northeastern area is separated from the northwestern 
area by igneous intrusives. The northeastern area has for a northern 
and eastern boundary the State lines. Its southern boundary is an 
east and west line, giving it a width north and south of a mile to one 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE VIII. 




FIG. 1.— wildcat point, showing depth of gorge cut in piedmont plateau by 

SUSQUEHANNA RIVER. 




Fig. 2.— LEVEL SURFACE OF PIEDMONT PLATEAU AWAY FROM MAIN DRAINAGE LINES. 
VIEWS OF PIEDMONT PLATEAU. 



MARYLAND GEOLOGICAL SURVEY 89 

and five-eighth miles, and a length of from seven to ten and a half 
miles. 

As the separation between it and the formation to the south must 
be made almost wholly on the character of the soil, and is a separation 
between soils derived from the decay of a muscovite-biotite-gneiss and 
the decay of a biotite-granite-gneiss, sometimes carrying muscovite, 
this boundary is somewhat hypothetical. 

In a general southwest direction from Calvert there are a few scat- 
tered occurrences of a micaceous (muscovite-biotite) gneiss. These 
may be either alteration phases of the granite-gneiss under pressure, 
or inclusion of the mica-gneiss. 

There is a considerable area of rock to the southwest outcropping 
on the Susquehanna, where it is about a mile in width, which extends 
eastward, pinching out about a half mile east of Liberty Grove. 
This exhibits the characteristics of the mica-gneiss and is inter- 
preted as an inclusion of the mica-gneiss within the igneous forma- 
tions. 

The mica-gneiss offers little resistance to weathering and is thor- 
oughly decayed when exposed in road cuts and railway cuts. The 
Susquehanna and the Big Elk Creek alone cut into the solid rock. 
The formation is so varied in character and in the amount of mica or 
of feldspar carried by it that, while often quite worthless for 
economic uses because of an excess of mica, it may locally become a 
fair building-stone. 

It has been used as such in Pennsylvania, but is not quarried in 
Cecil county. 

It is abundantly traversed by pegmatite and quartz veins; the 
former two feet and upwards in width, the latter varying from a 
fraction of an inch to fifty or more feet. These veins usually strike 
parallel to either the cleavage or joint planes, and are composed 
of quartz only or of quartz, an alkali feldspar, muscovite and biotite. 

In Pennsylvania the pegmatites assume a commercial importance. 
At many localities they are quarried for feldspar or for the kaolin 
to which the feldspar has altered. The " spar " quarries of Cecil 
county are not in the mica-gneiss, but traverse the igneous formations. 



90 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

The soil formed from the mica-gneiss contains sand, clay, muscovite 
and biotite. It has a yellow color and sparkles with muscovite. 

The conspicuous presence of this mineral has given rise among 
the farmers to the name " isinglass soil." 

In this and other characters it presents a considerable contrast to 
the soil derived from the ultrabasic and basic rocks bordering the 
mica-gneiss in the western half of the county, but graduates almost 
imperceptibly into the less micaceous clay loam derived from the 
granite-gneiss adjacent to the mica-gneiss in the eastern half of the 
county. 

IGNEOUS INTRUSIVES. 

The mica-gneiss constitutes the only sedimentary formation among 
the crystallines of Cecil county. 

That the other members of the crystalline belt are igneous material, 
more or less metamorphosed, will become clear as the discussion 
proceeds. 

These igneous rocks follow closely the strike of the sedimentary 
formation. They are successively exposed on the Susquehanna river 
and trend northeast, passing out of the county into Pennsylvania and 
Delaware. 

The Granite-Gneiss. — Granitoid rocks are exposed on the Sus- 
quehanna for some nine miles, but not uninterruptedly. An inclu- 
sion of mica-gneiss separates the granite-gneiss into two portions. 
The southern portion is traversed by dikes and larger intrusive 
bodies. The Susquehanna granites are medium-grained, light-colored 
rocks, irregularly marked by dark biotite or hornblende. 

These granitoid rocks, so finely exposed by the erosion of the Sus- 
quehanna, and so favorably situated for quarrying, have long been 
recognized as the most satisfactory building stone of the county. 

Their extension northeast from the Susquehanna across the county 
has not previously been recognized. 

Like the other formations, the granite-gneiss crosses the county 
to the northeast and disappears under Potomac gravels in the vicinity 
of Newark, I )elaware. 



MARYLAND GEOLOGICAL SURVEY 91 

Geologists have heretofore limited it on the east by a boundary 
line extending' from Harrisville south to Frenehtown. It is true 
that the exposures of granite-gneiss become much less conspicuous 
or cease altogether in the vicinity of this old boundary. The fact 
that east of this line lies the area of undissected plateau-land, which 
has already been described as better serving the purposes of the agri- 
culturist than of the geologist, explains the absence of exposures. 
The soil remains the same as that to the west where it is visibly the 
residual soil of granite. It is also uniform with that farther to the 
east where streams are cutting through the plateau-land and exposing 
a granite-gneiss. 

Moreover, obscure exposures and residual boulders of the granite- 
gneiss are not altogether absent from the intervening area. Just 
northwest of Principio, granite-gneiss is exposed. It can also be 
seen in ledges and great boulders a little more than halfway from 
College Green to Bay Yiew. South of Bay View granite-gneiss is 
exposed in Stony Run, Northeast and Little Northeast creeks, and 
along the Baltimore and Ohio Railroad tracks. It has been quarried 
at Leslie for the stone-work of the railroad trestle and a small quarry 
has also been opened on Stony Run, one mile southwest of Leslie. 
There are fine exposures of the rock at the crossing of Northeast 
Creek by the Pennsylvania tracks, and it may be seen in the bed of 
the stream where it is crossed by the highroad from Perryville to 
Elkton. This district, south of Bay View, is overlain by gravels and 
the buried rock-formation is only exposed where the streams have 
cut through the gravel. 

The rock of these exposures is either a hornblende-granite, or a 
biotite-granite. It is a medium grained and light colored rock, tra- 
versed irregularly by dark hornblende or biotite bands. It is a 
massive rock as a whole, but may locally show extreme foliation. 
The strike of the schistosity is northeast. It is essentially like 
the Susquehanna granites, but cannot be advantageously quarried 
because it is overlain by a considerable depth of decayed rock and 
no stream has cut deep enough to expose the solid formation. 



92 THE OBYSTALLINE BOOKS OF CECIL COUNTY 

To the east of Bay View, Little Elk and Big Elk creeks again 
uncover the granite-gneiss. Between Childs and Leeds on Little Elk 
Creek, there are excellent exposures of granite-gneiss. It is here a 
somewhat darkly colored, massive hornblende-granite, carrying very 
little biotite. The strike of the schistosity is 1ST 60° E and the dip 
30° to the southeast. 

The same rock shows itself all the way up the creek to the crossing 
of the road from Blue Ball to Eair Hill. On Big Elk Creek the first 
exposure is some five-eighths of a mile south of Banks, where there 
is a small abandoned quarry by the roadside showing a massive 
biotite-granite-gneiss. Erom this point up the stream to Appleton 
the rock is exposed at intervals. It bears both micas and sometimes 
hornblende also. 

A- the granite-gneiss approaches the mica-gneiss it becomes more 
micaceous and the separation between them is sometimes an arbitrary 
line. Large exposures, however, show a distinctly sedimentary char- 
acter in the latter and an igneous character in the former. Except 
where it approaches the mica-gneiss the granite-gneiss shows an 
increasing basicity both to the north and to the south. 

The granite-gneiss is thickly traversed by quartz veins and basic 
dikes. Scarcely a quarry is free from these dikes. Within a distance 
of less than a quarter of a mile thirteen such dikes occur. There are 
also larger intrusive masses exposed at Blythedale, Theodore and Bay 
View. These and the more important dikes will receive separate 
treatment. 

Throughout the level portions of the plateau, quartz vein-rock 
is universally distributed and is made use of as road-material. There 
are also numerous limited bands of red soil mixed with fragments 
of decayed amphibole-schist. 

This soil, with the associated amphibolite, undoubtedly represents 
basic dikes. As they can not be traced continuously and were usually 
quite limited in width, they were not, in most cases, mapped. 

Gabbro and Meta-Gabbbo. -The belt which borders the granite- 
gneiss on the north is composed of gabbroitic rocks — hypersthene- 
gabbro or norite, quartz-hornblende-gabbro, hornblende-gabbro or 



.MARYLAND GEOLOGICAL SURVEY 93 

meta-gabbro. This belt lias an exposure for a mile and a half on the 
Susquehanna river and becomes narrower to the northeast, disappear- 
ing altogether about three-fourths of a mile east of Lombard. 

Outside of this belt, gabbroitic rocks occur about one mile south 
of Iron Hill station, on Grays Hill and on the right bank of Big Elk 
Creek, two miles north of Elkton. These are outliers of the gabbro 
area of Chestnut Hill and Iron Hills in Delaware. 

The gabbro is typically a medium-course-grained granular rock, 
varying in color from a greenish grey to a brownish black. The 
medium dark tints are prevalent and serve to separate the gabbro 
from the granite-gneiss. The constituents can usually be distin- 
guished in the hand specimen and are a reddish brown or greenish 
brown hypersthene, often with a bronzy lustre, green diallage and a 
greenish grey or opaque white feldspar. 

To the southward these fresh appearing hypersthene-gabbros or 
norites grade into rocks in which the hypersthene is altering or has 
completely altered to hornblende. Such a zone of hornblende rocks 
or meta-gabbros borders the fresh norite on the south and composes 
the mass north and east of Calvert. These rocks, in turn, show the 
addition of quartz, a blue quartz conspicuous in the hand specimen, 
and with a slight increase in the acidity of their feldspar become 
quartz-biotite-hornblende-gabbro. This quartz-gabbro passes almost 
imperceptibly into hornblende-biotite-granite and this into a biotite- 
granite, the formations thus increase in acidity southward. 

Meta-Pyroxenites and Meta-Peridotites (Amphibolite, Serpen- 
tine and Soapstone). — For five-eighths of a mile from the northern 
limit of the gabbroitic material to Bald Friar, the Susquehanna cuts 
through a belt of soft and sometimes soapy greenstones. 

These greenstones represent various phases in the metamorphism 
of non-feldspathic igneous rocks. This belt widens to the northward 
and, with a width on the Mason and Dixon Line of three and one- 
eighth miles, passes, north of Kock Springs, into Pennsylvania, 
where it trends to the east and sweeps southward into Cecil county 
at four points between Eock Springs and Fair View. The last 
exposure is some sixteen and a half miles east of the Susquehanna 



94 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

river. The two more easterly of these occurrences are disconnected 
at the surface from the main mass by gabbro. 

There are also five lens-shaped inclusions of these ultra-basic 
int rushes within the gabbro area, three within the mica-gneiss for- 
mation, and some dikes of the same, south of Conowingo and at 
Oakwood. The dikes will be discussed later (pp. 97-100). 

The greater portion of this ultrabasic material has undergone com- 
plete alteration to serpentine. So thorough is the transformation 
throughout the mass of the formation that the original characters 
of the rock may only be determined through microscopic study. 

At scattered localities along the southern periphery of the serpen- 
tines, gradations into only partially altered pyroxenites and peridotites 
may be observed in the field. Such passage into well-recognized 
pyroxenites and peridotites is also exhibited in the dikes above men- 
tioned and in the lens-shaped included masses. 

This is the belt that has been generally known as the " State line 
serpentines" because the serpentine occurs for fully sixteen miles 
along the boundary between the states of Pennsylvania and Maryland. 
The serpentine is most varied in color and general appearance. It 
ranges in tint from a light buff, or a light yellowish, green, to a rich, 
deep emerald green or a dark blue green. 

Where the serpentine possesses a soft earthy texture, the colors are 
usually light in tint. Where it is compact and massive there is a 
deepening of the green tones, while a schistose or fibrous character 
is associated with a greyish green shade, which is due to the develop- 
ment of either talc, asbestos or tremolite. 

The rock possesses no original structural planes, but exhibits more 
than one system of secondary planes produced by pressure acting 
upon a massive rock. The master-joints are nearly vertical and strike 
northeast and southwest. The joint faces are often slicken-sided. 

The metamorphism of the original ferromagnesian silicates (pyrox- 
ene, amphibole and olivine) into the hydrous magnesian silicate, 
serpentine, is accompanied by the liberation of iron oxides and silica, 
in the form of hematite or limonite and quartz or opal, or a yellow 
limonitic jasper or chalcedony. 



MARYLAND GEOLOGICAL SURVEY 95 

The ground is strewn with these rusty yellow silicious iron-stones, 
which exhibit more or less of a honey-comb structure due to a finally 
complete removal of the magnesian silicate. 

Serpentine is always accompanied and is sometimes completely 
replaced by a final alteration product talc (steatite, soapstone). 
Soapstones are therefore also of frequent occurrence in serpentine 
areas. 

With the serpentines are also associated amphibole schists contain- 
ing asbestos, tremolite, anthophyllite, actinolite or chlorite, and rep- 
resenting the metamorphism of pyroxenites. All these associated 
types, the original peridotites and pyroxenites, the serpentines repre- 
senting one phase of metamorphism, the amphibolites representing 
another phase of metamorphism, the soapstones and the iron-stones 
representing an extreme phase of alteration, are considered a geologic 
unit and mapped as a single formation. 

The soil to which they give rise and the aspect of the country 
underlain by them is most distinctive. The soil is known by the 
farmers as the " honey-comb-rock soil " and its sterility is recognized 
by them. Where the rock comes close to the surface, either out- 
cropping or with scanty covering, as is often the case, the soil is the 
color of the rock, yellowish-green. Where the accumulation of a 
greater depth of mantle-rock has permitted chemical processes to take 
place, the soil, rich in oxidized iron, possesses an intensely red color. 

The main serpentine belt is locally known as "the barrens" and 
strikingly merits that name. At the border of the serpentine belt the 
aspect of the country alters abruptly. One leaves behind a prosper- 
ous and pleasing agricultural region and enters a wild and desolate 
district supporting a scanty vegetation. Dwarfed white pines, cedars 
and the cat-brier thinly clothe the rugged hills and render travel 
across country difficult. 

From the summit of hills within or adjoining " the barrens " the 
distribution of the serpentine can be traced by the peculiar character 
of the vegetation it supports. (See Plate IX, Fig. 1.) 

The barrens are sparsely settled and the houses small and poor, 
for the most part. The comparative sterility of the soil may be due 



96 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

to its thinness and inability to hold water rather than to its chemical 
composition. With greater depth, fertility increases, good water is 
abundant, the country healthful and picturesque, and with judicious 
fertilizing the soil becomes productiYe. 

The State line serpentines played an important role in the early 
history of mining industries in Cecil county. This was due to the 
chrome ore which they contain. 

The first discovery of chrome ore in America was made by Isaac 
Tyson at the Bare Hills, Baltimore county, in 1827. Soon after this 
discovery Mr. Tyson's son started the manufacture of pigment from 
chrome ore and this industry at once brought the ore into demand. 
A stray boulder containing ore, used to support a barrel in the 
market-place of Belair, led to the discovery of a fresh source of the 
material in Harford county. It was then, for the first time, noted 
that the ore was confined to the serpentine rock and this formation 
was accordingly traced across the Susquehanna into Cecil county, 
and in 1828 a chrome mine was located about five miles northwest of 
Rising Sun, which was for some time the richest known mine in 
America. 

The neighborhood of this deposit, the Wood's mine, has also come 
into prominence as a collecting ground for some of the rarer minerals 
associated with the serpentine, such as brucite, clinochlore, deweylite, 
zaratite, picrolite, magnesite, hydromagnesite and williamsite, 1 which 
have been found here. 

Along some of the streams of the belt there occur more or less 
valuable deposits of chrome sand. This sand has been derived from 
the weathering of the serpentine. The granules of the chrome ore 
have been sorted out, transported and deposited by water. 

In the serpentine as in the mica-gneiss there are pegmatite veins. 
Some df these are of considerable size and have been opened for the 
feldspar. 

The veins usually, but not always, strike northeast-southwest. 

There are a number of abandoned openings for feldspar in the 
r< aion of Goat Hill and just to the north of the State line. One ami 

1 This locality is designated "Texas," Lancaster Co., Pa. in Dana's Mineralogy. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE IX. 




FtG. l.-VIEW SHOWING BARRENS UNDERLAIN BY SERPENTINE. 



Fig. 2.— VIEW SHOWING FARM-LANDS UNDERLAIN BY GRANITE-GNEISS. 
VIEWS OF PIEDMONT PLATEAU. 



MARYLAND GEOLOGICAL SURVEY 97 

a half mile west of Sylmar, north of the State line, two feldspar 
quarries, the Tweed quarry and the Walker quarry, are being worked 
in a vein striking east 60° south. North of Sylmar are some aban- 
doned openings. At the fork in the road, three-eighths of a mile east 
of Kock Springs, are two feldspar openings in a vein some six to eight 
feet wide, which have been abandoned for three years. They are 
known as the Tweed quarry and the Riley quarry. The serpentine 
bordering the vein has altered to talc. In the spring of 1901 a pro- 
ductive opening was made close to the abandoned Tweed quarry. 
The vein strikes N" 30° E. The spar is hauled to Conowingo and 
thence shipped to Trenton. 

About one and a half miles east from Rock Springs, on the edge 
of the serpentine, is the Taylor feldspar and flint quarry. This vein 
strikes northeast-southwest and has considerable width. The material 
is shipped to Trenton, ISTew Jersey, and to Liverpool, Ohio. The 
quarries are idle at present. 

Magnesia has also been mined in the serpentine, but only in small 
quantities. The openings, which are now abandoned, are situated 
in the Pennsylvania extension of the serpentines. The iron ores, 
limonite and hematite, have been mined in the serpentine of Penn- 
sylvania, but the Cecil county serpentine shows no iron ore pits. 

On the roads from Conowingo to Rock Springs and* from Cono- 
wingo to Pilot, there are pits in the serpentine made in search of 
gold ore, at the instigation of a syndicate known as " The Klondike 
Company." This company purchased the option on considerable 
property to the north of Conowingo with the expectation of finding 
the rocks richly auriferous. The results did not meet their expecta- 
tions and the company has been inactive for more than a year. 

DIKE ROCKS AND OTHER INTRUSIVES IN THE GRANITE-GNEISS. 

From the mouth of Rock Run to Perryville the granite-gneiss is 
thoroughly penetrated by dikes varying from one foot in width to 
several hundred feet. There are two just above Rock Run four feet 
in width striking N 15° and N 50° E, respectively. One-eighth of a 
mile south of Rock Run there occurs a dike eight and one-half feet 



98 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

in width striking !N" 40 °E. South of this locality at the first 
road to the northeast there are five small dikes striking parallel to 
the others. About a quarter of a mile south of this and opposite the 
Episcopal church of Port Deposit, there is a dike ten and a quarter 
feet wide striking X 25° E and dipping 45° southeast. Close by it 
is a very small dike. 

There are doubtless others in the town of Port Deposit concealed 
by the houses which crowd against the granite bluff. 

An eighth of a mile south of the southern end of Port Deposit 
there is a fresh coarse-grained diabase dike some fifty feet wide. 
This rock is very unlike the green hornblendic rock of the other 
dikes and it is thought to be a much more recent intrusive of 
Triassic age. Its petrography is discussed on page 140. 

Between this dike and the stream known as Happy Valley Branch, 
one fourth of a mile to the south, there are 13 basic dikes, approxi- 
mately, 3 ft., 8 ft., 1 ft., 4 ft, 12 ft., 12 ft., 10 ft., 11 ft., 4 ft, 2 ft. 
6 ft. and 6 ft. wide, respectively. 1 They strike N ± 45° E. 

South of Happy Valley Branch there occur successively a two- 
foot dike, a four-foot dike, another two-foot dike, and a dike about 
30 feet wide, opposite the track-watchman's box. Then follows an 
intrusion of a fine-grained dark-colored yet quartz-bearing and acid- 
appearing rock which continues a short distance beyond the creek. 
On the south bank of the creek this is exposed in an abandoned 
quarry; while north of the run it is penetrated by two hornblendic 
dikes. 

The quarry rock shows a southeast dip due to creep. 

Immediately south of this quarry a fine-grained granite is pene- 
trated by a basic dike (meta-gabbro) three or four feet wide and fol- 
lowed by 200 feet of meta-gabbro. South of this the acid intrusive 
(meta-rhyolite) again appears. This formation is here amygdaloidal. 
Some 200 feet south of the meta-gabbro another dike of that rock 
appears of the same width. 

1 These and all other estimates of the width of dikes were made by pacing, and are, 
of course, approximate. 



MARYLAND GEOLOGICAL SURVEY 99 

South of this point the exposures are not good. A fine-grained 
hornblendic granite-gneiss shows in the soil. One half a mile above 
Frenchtown the meta-rhyolite is exposed in places. It occupies the 
valley of the little creek at this point and probably extends to the 
northwest along the Susquehanna. 

At Frenchtown the granite-gneiss is actively quarried, but to the 
east and north the rock is meta-rhyolite. This is largely concealed 
beneath the gravels, but can be seen along the roadway from Aiken 
to Blythedale and at Blythedale. East and north of this village it 
is completely buried, but reappears in the neighborhood of Bay View. 
Here a large body of it, more than a mile in width, strikes to the 
northeast. It is exposed by the streams which cross this area. It 
is also well exposed at the junction of the two main branches of 
Stony Eun, on Northeast Creek and on the Little Northeast, where 
it appears in a considerable cliff. 

At the former locality, one half mile northeast of Bay View, 
boulders of the meta-rhyolite are piled up in picturesque confusion. 
The stream dashes over the rock in a series of cascades which give 
charm and wildness to the glen. The spot is known as " Gilpin 
Rocks " and is a resort for picnic parties (Plates II, Fig.. 2, and XI). 

Here the prevailing color of the rock is green, though some fresh 
grey material may be found. A light-colored aplitic rock penetrates 
it in narrow dikes. Hornblende, chlorite and epidote characterize 
the green material in the hand specimen. 

In a road-cut on the Baltimore and Ohio railroad just before it 
crosses Principio Creek, both fresh and disintegrated meta-rhyolite are 
exposed. It is also uncovered in the bed of Principio Creek to a 
point within a half mile of Principio Furnace, where it gives way 
to the enclosing hornblende-granite. 

An offshoot of the meta-rhyolite appears as a dike, about twelve 
feet in width, at Mechanics Valley. 

The rock was found comparatively fresh in the Susquehanna 
exposures, in the Baltimore and Ohio Railroad cut and a short dis- 
tance north of Frenchtown, where it had been blasted in making 
place for a telephone pole. 



100 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

The fresh material is light grey, hard, compact, aphanitic, with 
inconspicuous quartz and feldspar phenocrysts. An analysis and a 
petrographic description of this interesting intrusive arc given on 
pages 136-139. 

A meta-gabbro dike of considerable width can be traced inter- 
mittently across the county from Zion to Newark, Delaware, where 
it shows itself to be an offshoot from the Delaware gabbro mass. 

An offshoot from the Cecil county gabbro occurs two miles west 
of Rising Sun on the road to Porter Bridge. 

These are the more important of the many meta-gabbro dikes in 
the granite-gneiss. 

INTRUSIVES IN THE GABBRO BELT. 

The intrusives in the gabbro belt are of a more basic character than 
those in the granite-gneiss. One-fourth of a mile south of Conowingo 
Station there is a dike of light green meta-pyroxenite, about forty feet 
in width. This is followed to the south by a less altered pyroxenite, 
about, twenty feet in width, and this in turn is succeeded by a dike 
which has altered to steatite, or soapstone, not more than twenty-six 
feet wide. A squeezed micaceous vein intervenes between this steatite 
and a similar eighteen-foot steatite dike on the south. This is followed 
by a pegmatite vein, eighty-four feet wide, and some more soapstone 
rock, forty-four feet in width. This soapstone dike is opposite the 
watchman's box, and after an interval of approximately forty feet of 
norite, a third dike of soapstone occurs some thirty feet in width. 

About a quarter of a mile to the south, at the second rock-cut 
below Conowingo and shortly before the quartz-hornblende-gabbro 
belt is reached, there is a pyroxenite dike approximately sixty feet 
wide. A pyroxenite dike, which outcrops just east of Oakwood, is 
probably its continuation, while two small steatite dikes outcropping 
southwest and west of Oakwood appear to be the continuations of 
two of the steatite dikes observed below Conowingo. 

DIABASE DIKES. 

Beside these altered dikes there is a fresh diabase dike which 
extends interruptedly in a northeast-southwest course across the 



MARYLAND GEOLOGICAL SURVEY 1.01 

plateau. This is traced mainly by means of a trail of boulders and its 
limits are accordingly somewhat hypothetical. It probably enters 
the State a short distance west of Sylmar and traverses the county 
a little to the southeast of Rising Sun, Colora and Liberty Grove. Its 
course is shown on the map in dark red. A rotten, yellowish red rock, 
breaking in cuboidal blocks with aphanitic green centers, occurs at 
the following points in the neighborhood of Rising Sun: three-six- 
teenths of a mile north of the railroad on the highway which crosses 
the Central Division of the Pennsylvania road, north of the town; 
in the railroad cut northeast of the station and at other points to the 
southwest. This was thought to be the weathered diabase and was 
made use of in mapping the dike. 

South of this dike and roughly parallel with it occurs another but 
coarser grained dike of the same material. It has already been men- 
tioned as located north of Happy Valley Branch. At Williamson's 
Point on the Susquehanna, one mile north of the State line, a 3 to 
4 inches wide miniature diabase dike traverses the gneiss. 

These diabase dikes are the attenuated continuations of the great 
intrusion of igneous material in the Triassic of the Atlantic coast. 
Mt. Tom and Mt. Holyoke, the Palisades of the Hudson and the 
Highlands of New Jersey represent the great masses of this intrusive 
and extrusive body. In Pennsylvania this period of igneous activity 
is represented only by numerous dikes and larger intrusive bodies 
of diabase, some of which can be traced more or less continuously 
across the state and into Maryland. The Cecil county diabase dikes, 
therefore, although no external evidence of their age is furnished 
within the county, must be of late Triassic age, because they are 
part of a formation which to the northeast is intrusive in Triassic 
sandstones and shales. 

PEGMATITE VEINS. 

Mention has already been made of the numerous pegmatite and 
quartz veins which traverse all the formations indiscriminately. 
Only those pegmatite or quartz veins which are exposed and exceed 
fifty feet in width have been mapped. The abundance of the quartz 



102 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

veins, which are concealed by soil, is attested by the innumerable frag- 
ments of this material which are strewn throughout the plateau. The 
much more ready disintegration of the bounding rock, compared with 
that of the vein material, results in a soil quite free from boulders 
of the underlying rock, but full of " flint stones." 

The quartz often contains tourmaline crystals and is coated with 
a red or black stain. 

The quartz veins are plainly precipitations in cracks and fissures 
from heated solutions and may be the work of descending, ascending 
or laterally moving water. The nature of the veins and the sur- 
rounding rock are such as to lead us to infer that descending silica- 
charged water and lateral secretion will explain their formation. 
The fissuring of the rock is due to diastrophic movements. 

The pegmatites bear evidence of a similar origin. They differ 
from the quartz vein only in the addition of an alkali feldspar and 
muscovite or biotite. This material may line both walls of a fis- 
sure, while the central mass is pure quartz. Such a pegmatite 
occurs half a mile above Conowingo Station. It has a width of some 
three hundred feet, with a central vein of quartz some fifty feet 
wide. It strikes E" 40° to 55° E, and is probably a part of the vein 
which has been so long quarried for " flint " at Castleton, on the 
Harford county side of the Susquehanna. 

A quarter of a mile south of Conowingo Station, also on the river, 
there is a pegmatite dike possessing a width of eighty-four feet. 

On Octoraro Creek, between the paper-mill at the fork in the road 
and the State line, there are three pegmatites of a granitic character. 
The constituents are quartz, microcline, muscovite and a little biotite. 
The first possesses a width of ninety feet. The second of these 
bodies lies about midway between the first and the State line, while 
the third and largest (100 ft.) is close upon the State line. 

The wall-rock is norite and meta-norite. This pegmatite is quar- 
ried on the west side of the creek, on Taylor's farm, for feldspar. 
It is said to have yielded some 10,000 tons of feldspar. Other flint 
veins also occur on the same farm. The " spar quarries " in the 
serpentines have already been mentioned and lie for the most part 
north of the State line. 



MARYLAND GEOLOGICAL SURVEY 



103 



The pegmatites may be composed almost wholly of a white alkali 
feldspar, as is the case in the vein just east of Rock Spring, where 
the vein is enclosed in steatite-serpentine rock. 

The pegmatites, offering as they do in many cases so sharp a 
contrast in chemical and mineral constitution to the bounding rock, 
can hardly be produced by lateral secretion. 

Percolating waters descending through a weathered zone of mater- 
ial, which has subsequently been removed (e. g. Triassic shales and 
sandstones), and ascending waters, which in their long circuitous 
route have acquired the acid silicates, may produce the pegmatites 
by their deposits in these fissures. Such an origin seems highly 
probable for the most silicious or the most feldspathic of the peg- 
matite veins. It does not necessarily explain all the pegmatites. 
There are some of a more granitic character to which an aqueo- 
igneous origin may be ascribed. 

Structural Relations and Age of the Crystalline Formations. 

the mica-gneiss. 

The Susquehanna section of the mica-gneiss shows a formation 
which, while finely gneissic at Bald Friar, passes northward into a 
conglomeritic phase. This, in turn, becomes a fine-grained sericitic 
or sometimes chloritic quartz-schist with more or less feldspar present. 




Fig. 5. — Diagram showing type of unsymmetrical overturned folding. 

Somewhat less than three miles north of the Mason and Dixon 
Line, the quartzose beds give place to a dark blue-black slate, which 
forms a continuation of the well-known Peach Bottom slate belt on 
the west side of the Susquehanna. The strike varies from 1ST 30° E 
to 1ST 70° E. Where cleavage is developed it dips steeply southeast. 
The stratification varies from horizontally with an undulating sur- 
face to verticality. The average inclination is ±35° and is uni- 
formly to the southeast. 



104 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

Unsymmetrical overturned folds, as shown in Figure 5, are dis- 
played, on a small scale, at Haines and at other localities. 

These minor folds may illustrate in miniature the large scale 
folding of the entire formation. 

There is no recurrence of lithologic units, by means of which the 
thickness of the formation can be ascertained, but the dips indicate 
more or less unsymmetrical overturned folds. The vertical beds 
may frequently represent the northwest limb of the folds, as is sug- 
gested on the section accompanying the geological map. 

Age. — The mica-gneiss of Cecil county contains within itself no 
clue to its age. The solution of this problem must be found in the 
stratigraphic relations which the formation may sustain to fossil- 
bearing sediments. 

Such stratigraphic relations do not exist in Cecil county, but are 
displayed in Pennsylvania and Delaware. The relation of the Cecil 
county mica-gneiss to a similar formation in these states must there- 
fore be indicated. 

The gneisses of the Philadelphia belt of crystallines (Chestnut 
Hill, Manayunk and Philadelphia schist and gneisses) are divisible 
into a mica-gneiss of sedimentary origin, and several, presumably 
intrusive, igneous bodies; peridotites and pyroxenites, largely repre- 
sented now by serpentines, gabbro and norite and two granite-gneisses. 
The formation into which these igneous rocks have intruded is a mica- 
gneiss, 1 stratigraphically continuous with and lithologically similar 
to the mica-gneiss of Cecil county. If the Wissahickon gneiss and 
the mica-gneiss of Cecil county are a unit, an inquiry into the struc- 
tural relations and age of the "Wissahickon gneiss becomes pertinent. 

The Peach Bottom slates, which appear to be a conformable mem- 
ber of the series of which the Wissahickon mica-gneiss is an upper 
member, have been referred by Professor James Hall to the 
( Jalciferous. 

This determination was made on the basis of some rather dubious 
fossils submitted to him by Persifor Prazer " and cannot, therefore, 

1 It is provisionally named the Wissahickon gtieiss from the creek along the banks of 
which it is finely exposed. 
2 Trans. Amer. Inst. Min. Eng., vol. xii, 1884, p. 358. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE X. 

4f * '*'' 




FIG. 1. -RAILROAD CUT IN CONTORTED GNEISS, ABOVE BALD FRIAR. 





















FlG. 2.— NEARER VIEW, SHOWING CHARACTER OF FOLDING. 
VIEWS OF PIEDMONT PLATEAU STRUCTURE. 



MARYLAND GEOLOGICAL SURVEY 



105 



be considered perfectly trustworthy. Nor are the apparent strati- 
graphic relations necessarily the true relations of the two formations. 

Another hypothesis as to the relations will be discussed later. 

The stratigraphic relations which the Wissahickon mica-gneiss was 
found to sustain to a crystalline limestone in Delaware and Pennsyl- 
vania, have a bearing upon the age and origin of this formation and 
may ultimately prove the means of determining both questions. 

The facts are as follows : Some five miles northeast of the extreme 
northeastern corner of Cecil county, in the state of Delaware, are four 
abandoned limestone quarries, situated in the mica-gneiss formation 
and approximately normal to the strike. The limestone is a white, 
crystalline, saccharoidal formation, somewhat stained with iron oxide. 
It shows considerable plication and in each quarry is brought to the 




Fig. 6. — Section showing conformable contact of limestone with overlying mica- 
gneiss. 



surface by a low unsymmetrical anticlinal fold. The northwest limbs 
of the anticlines are always steeper than the southeast limbs. The 
strike varies from 1ST 30° E to 1ST 60° E; the southeast dips are 15°, 
25° and 35°; the northwest dips are 55° and 65°. A massive mica- 
gneiss overlies the limestone with a sharp conformable contact. 

Essentially the same conditions prevail northeast of Cecil county 
and south of Landenburg, Pennsylvania. Here again gentle unsym- 
metrical anticlines have brought a blue or white crystalline limestone 
so near the surface that quarries in the formation were opened by 
Isaac Sharpless, by David Nevins and by John ISTevins. At John 
Kevins' quarry the mica-gneiss and limestone of the northwest limb 
of the anticline are solidly welded together and show no evidence 
of adjustment. 



106 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

The contact plane of the gneiss and limestone is a plane of weak- 
ness and is, therefore, locally at least, sometimes a thrust plane. 
This is the case at the Chester County Poorhouse, seven miles west 
of West Chester, where the mica-gneiss has been shoved over the 
limestone, cutting off some portion of the latter. At the Avondale 
quarries (Bakers Station, Pa.) the reverse adjustment has taken place 
and a thrust of the limestone against the mica-gneiss occurs. While 
in an abandoned quarry only a quarter of a mile to the west of this 
locality a conformable contact of gneiss and limestone can be seen. 
As the mica-gneiss is approached the limestone shows interstratified 
mica-gneiss beds. 

That mica-gneiss conformably overlies limestone is also found to 
be the case in the Doe Run district and in several limestone quarries 
west of West Chester. In short, in the numerous exposures of lime- 
stone and mica-gneiss southeast of Chester Valley, conformable strati- 
fication is the rule and adjustment is local and exceptional. 

2\To fossils have been found in these limestones. They have been 
referred by the geologists of both the First and the Second Geological 
Surveys of Pennsylvania to the period represented by the Chester 
Valley limestone, i. e., to the Cambrian-Silurian period. They per- 
fectly resemble these limestones, lithologically, chemically, in char- 
acter of crystallization and in prevailing structure. Their exposures 
are not far to the southeast of Chester A T alley from which they are 
separated by overlying mica-gneiss and Hudson schists. 

Not only does the Wissahickon mica-gneiss overlie limestone, which 
furnishes no evidence of an earlier age than that of adjacent Cam- 
brian-Silurian limestones, but where the mica-gneiss and Hudson 
schists, which overlie the Chester Valley limestone, adjoin, there is a 
perfect lithologic gradation between the two formations and an 
apparent continuity of structure. This can be observed in the sec- 
tions furnished by the east and west branches of the Brandywine. 

While in typical development they are very distinct in character, 
when adjacent it is practically impossible to place a satisfactory line 
of separation between the two formations. That this is the case in 
the Susquehanna section in Cecil county has already been stated. 



MARYLAND GEOLOGICAL SURVEY 



107 



The following section illustrates the structural relations of the 
Wissahickon mica-gneiss farther north: 




Fig. 7.— Generalized section from Merion, Pa., to Haverford, Pa., showing possible 
structure of crystalline formations. 

N F. = Newark Formation. S. = Serpentine. 

PI S. = Hudson schists. W M-G. = Wissahickon Mica-gneiss. 

Gb-Gn. = Gabbro-gneiss. C-S L. = Cambrian-Silurian limestone. 

I = Diabase. 

The key to the structural relations of these formations is to be 
found in Pennsylvania and more detailed investigation will either 
establish the conclusions reached in a rapid preliminary survey 
without the aid of topographic maps, or furnish other stratigraphic 
details. At present the facts seem to warrant the following conclu- 
sions: 

The mica-gneiss of Cecil county is a geologic unit, though form- 
erly regarded as two distinct formations: a " hydromica schist" in 
the west and a " gneiss " in the east. It is the same formation as 
the Wissahickon gneiss of Pennsylvania. The Wissahickon gneiss 
conformably overlies limestone, which is presumably, though not 
proven to be, Cambrian-Silurian. It adjoins, in southeastern Penn- 
sylvania, mica-schist, which has been determined by fossils to be of 
Hudson age. With this Hudson schist it shows continuity of struc- 
ture and a lithologic graduation. The Wissahickon mica-gneiss shows 
no greater metamorphism than the adjacent Paleozoics and no closer 
folding. Unsymmetrical open folding is the rule, with a steep cleav- 
age dip to the southeast in both Paleozoics and mica-gneiss. 

If these conclusions stand, the Wissahickon mica-gneiss and its 
continuation in Cecil county must be referred to the Hudson divi- 
sion of the Lower Silurian period. This is in accord with the occur- 
rence, as a conformable lower member of the series, of the Peach 
Bottom slates, which have been referred to the Calciferous. 

The alternative conclusion is that the Wissahickon gneiss with its 



108 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

underlying limestone and quartzite, is separated from the Paleozoics 
on the northwesl by a fault and that it is pre-Oambrian. If this is 
the ease the apparent conformity of the ( 'aleiferous Peach Bottom 
slates and the Cecil county miea-gneiss is not the true relation of the 
two formations. A thrust fault must separate the mica-gneiss from 
the slates. This must also be the case with the Hudson schists and 
the mica-gneiss. While no evidence has vet been found of such a 
fault, and on the contrary proof of stratigraphic conformity has accu- 
mulated, there is one fact which may indicate a time break between 
the eastern gneisses and the western Paleozoics: 

The apparent confinement of eruptive material to the eastern 
belt of gneisses is suggestive of a time interval between the forma- 
tions. Professor George Huntington Williams 1 referred the eastern 
gneisses to an earlier age (pre-Cambrian) than the western Paleo- 
zoics of the Piedmont Plateau of Maryland. He emphasizes the 
greater degree of metamorphism exhibited by the former formations. 
This difference in degree of metamorphism does not deserve 
emphasis in Pennsylvania. The quartzite and crystalline limestone 
interstratified with the Wissahickon gneiss are no more thoroughly 
metamorphosed than is the recognized Paleozoic quartzite and crys- 
talline limestone. !Nor does the micaceous phase of the gneiss differ 
in the degree of metamorphism exhibited by it from the mica schist 
of Hudson age. 

Positive proof for or against the Paleozoic age of the Wissahiekon 
mica-gneiss is lacking. Until evidenee for or against a faulted struc- 
ture has been procured, or fossils are found in the interstratified 
limestone, the age of the Wissahickon gneiss and hence of the Cecil 
county mica-gneiss must be considered as undetermined. 

It is either pre-Cambrian or Lower Silurian. 

THE ERUPTIVE ROCKS. 

The question next occurs, are the igneous formations intrusive in 
the mica-gneiss or do they altogether underlie it? 

The meta-peridotites and pyroxenites show the usual character of 
intrusives; dike-like exposures, apophyses, the occurrence of discon- 

1 Bull. Geol. Soc. Amer., vol. ii, L891, p. 316. 



MARYLAND GEOLOGICAL SURVEY 109 

nected dikes and included bodies of the same rock in the neighbor- 
hood of the large masses, and contact action upon the mica-gneiss. 
The gabbro belt is so intimately related to the meta-pyroxenites and 
meta-peridotites that it is highly improbable that one mass is intrusive 
and the other not. There is nothing in the contours and contacts of 
the gabbro belt that is inconsistent with an intrusive origin. The 
meta-gabbro dikes in the granite-gneiss are presumably related to 
the main gabbro body and indicate an intrusive character relative to 
the granite-gneiss. 

The same reasoning applies, though with less force, to the granite. 

It is true that the contact of the granite-gneiss and gabbro is 
usually one of gradation. This fact, however, is not inconsistent 
with the intrusion of the latter into the former, or of both into the 
mica-gneiss. The contact of granite-gneiss and mica-gneiss is not 
uncovered. 

Dynamic movements have affected gabbro, granite and mica-gneiss 
alike. No more movements are found recorded in one formation 
than in the others. Cleavage dips and joint planes are parallel in 
these formations. 

This granite has been considered an intrusive body by other inves- 
tigators in Maryland and the writer finds no proof against that con- 
clusion while still holding it provisionally in the absence of positive 
proof in Cecil county. 

If the igneous formations are intrusive in the mica-gneiss they are 
of a later age and are either pre-Cambrian or Palaeozoic. That they 
cannot be ascribed to a later era than the Palaeozoic is rendered plain 
by the fact that they nowhere intrude into the Mesozoic formations 
which cover them in the north. 

They are for the present involved in the obscurity which surrounds 
the age of the mica-gneiss. 

The petrographic study of the eruptive rocks brings up another 
question in regard to their origin. Are the igneous formations a 
geologic unit representing a single intrusion or are successive intru- 
sions represented by the different petrographic types? It is highly 
probable that the igneous rocks of the county are the differentiation 



110 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

products of a single magma. The problem is one of the time of the 
differentiation. Was the magma differentiated before or after intru- 
sion? The types can be explained on the supposition that differenti- 
ation took place both before and after intrusion. 

The granitic magma of medium acidity was first intruded. 1 In 
this magma some differentiation took place, thus producing the ap- 
pearance of gradation along the gabbro contact. Subsequently a 
more acid magma (meta-rhyolite) filled the fissures in the cooled and 
contracted granite. The gabbroitic intrusion followed, penetrating 
into the mica-gneiss, the granite-gneiss and the meta-rhyolite, and 
representing the basic residual after the separation of the rhy otitic 
magma. 

Last of all and representing a final differentiation of the magma, 
there was intruded the ultrabasic material which gave rise to pyrox- 
enites and peridotites (serpentine). 

Petrographic study of the igneous types shows that there is a 
central body of intermediate acidity. Into this body are intruded 
material both of greater acidity and greater basicity. On either 
margin of the central mass, with some intermediate types, are succes- 
sively basic and ultrabasic types. 

The petrographic succession is as follows, passing from the most 
acid type northward: 

Basic biotite-granite (biotite-quartz-monzonite), containing dikes of 
a more acid character (meta-rhyolite). 

Basic hornblende-biotite-granite (hornblende-quartz-monzonite). 

Qnartz-biotite-hornblende-gabbro. 

Quartz-hornblende-gabbro. 

Hornblende-norite and quartz-norite. 

Norite and hypersthene-gabbro. 

Pyroxcnilr. 

Peridotite. 

'The granite masses elsewhere through the State have been considered younger 
than the gabbro ft'. 8. Geol. Survey, L5th Annual Rep't, p. 788). If this is the ease 
in Cecil county the gabbroitic dikes in the granite cannot be apophyses of the main 
gabbro mass. The writer has considered them to be such in one case at least, and 
on this basis the gabbroitic intrusion is held to be subsequent to the Invasion of the 
granitic magma. 



MAE YL AND GEOLOGICAL SURVEY 111 

On the south, the succession is more or less concealed by overlying 
deposits. That a similar succession might be uncovered here, is 
indicated by the reappearance of hornblende in the southern margin 
of the granite-gneiss and by the occurrence of outliers, in the gravel 
areas to the south, of gabbro, pyroxenite and serpentine. These out- 
liers occur in the neighborhood of Elkton on the margin and south 
of the plateau. They are part of a more extended gabbro-pyroxenite 
area in Delaware. 

In Harford county, southwest, of Havre de Grace, a. continuation 
of this gabbro belt has been mapped. 

The existence of a zone of intermediate and connecting types 
between granite and gabbro, as suggested by Dr. Leonard, 1 may easily 
lead to an unwarranted emphasis of insignificant connecting types; 
but, in general, the writer agrees with his observations rather than 
with those of Dr. Grimsley, 2 who describes an eruptive contact be- 
tween granite and gabbro on Octoraro Creek in the vicinity of 
Porter Bridge. 

The granite contains here, as elsewhere, dark, fine-grained basic 
segregations. They do not change in character or increase in number 
as the gabbro belt is approached. The rocks of this belt contain 
similar segregations. 

These oval or irregularly shaped patches vary in size from one 
inch (26 millimeters) to two or three feet (60 to 90 centimeters), 
and are frequently foliated in character owing to an excess of biotite 
over the other constituents, quartz and feldspar. Their longer direc- 
tion and their foliation, when present, are parallel to the schist- 
osity of the enclosing rock, which is usually coarser grained. 
There has been no difference of opinion as to the character of these 
segregation patches. The following table of their silica percentage 
and specific gravity determination with that of similar material form 
elsewhere, is taken, with some necessary corrections, from Dr. Grims- 
ley's paper: 

1 Amer. Geol., vol. xxviii, 1901, pp. 167-168. 

2 Jour. Cincinnati Soc. Nat. Hist., vol. xvii, p. 65. 



1 L2 



THE CRYSTALLINE ROCKS OF CECIL COUNTY 



Port Deposit, Maryland. 
Peterhead, Scotland 
Snap Fell, Westmoreland 

Greacly, Cornwall 

Barr-Andlau, Alsace 



Silica. 



Granite. Segregation. 



73.7 
73.70 
69 . 78 
69.64 

68.97 



62.2 

64 . 39 
56.95 

65 . 01 
57 . 89 



Specific Gravity. 



Granite. 



2.69 
2.69 
2.69 

2 . 72 
2.68 



Segregation. 



2.83 
2.73 



2.73 



While, therefore, these basic segregations cannot be considered a 
proof of eruptive contact between granite and gabbro, gabbro dikes 
in the neighborhood both of the northern and southern gabbro belt 
are considered contemporaneous intrusions of the same magma, and 
proof of an intrusive origin for the gabbro, subsequent to the granite. 

The relation of the norite to the pjroxenites and peridotites is more 
distinctly expressed. Between their alteration product, serpentine, 
and the norite can be drawn a distinct lino, and in the norite occur 
pvroxenite and peridotite dikes. The triangular area of serpentine 
at the head of Xortheast Creek, on the State line, is an apophysis 
from the " State line serpentines." 

Between this apophysis and Sylmar there is exposed an oval mass 
of serpentine which touches the State line, but lies mainly in Penn- 
sylvania. Southwest of Sylmar and just south of the junction of 
the Rising Sun and Calvert roads (by Mount Hope ( !hurch) 3 there 
is an oval mass of serpentine and peridotite, somewhat more than a 
half mile long and nearly one quarter of a mile wide. Two miles 
west of this locality and two miles north of Harrisville, is exposed 
another included nu^s of meta-peridotite. Notwithstanding the ap- 
parent sharpness of the boundary between meta-peridotite or meta- 
pyroxenite and norite, there are intermediate types along the border, 
norites in which the feldspar is reduced and pyroxenites containing 
feldspar. 

There are, in short, four igneous types amid all these gradations. 

An acid feldspathic type; an intermediate feldspathic type; a basic 
feldspathic type and a non-feldspathic type. 



MARYLAND GEOLOGICAL SURVEY 113 

These types, it is believed, represent differentiation of the magma 
before intrusion, while their gradations represent subsequent differ- 
entiation. 

PETKOGKAPHY OF THE CRYSTALLINE FORMATIONS. 1 

Mica-Gneiss. 

The mica-gneiss does not possess a uniform lithologic character, 
but is exceedingly heterogeneous. It is usually marked by an excess 
of mica, but this is not always the case. When either muscovite or 
biotite, or both micas, are conspicuous constituents, the rock is very 
schistose and coarsely crystalline. 

As mica becomes less prominent, the formation becomes finer 
grained, and either more gneissic or more quartzose. The amounts 
of quartz and feldspar present vary considerably, but neither is 
ever altogether absent. 

The most gneissic type is found in the exposure on the Susquehanna 
at Bald Friar and northward. At Haines, just north of the State 
line, the formation is very quartzose. Massive grey quartzose beds 
alternate with thin chloritic beds, which show slip cleavage. In the 
eastern part of Cecil county the formation is very micaceous. 

At Bald Friar the rock is fine-grained and a light shade of glisten- 
ing greenish grey. 

In the hand specimen muscovite, quartz, feldspar and epidote can 
be distinguished. The slides show abundant minute scales of mus- 
covite and clear granulated quartz as the predominant constituents. 

Muscovite is the alteration product of rounded grains of an alkali 
feldspar and also fills interstices. 

Quartz occurs in granulated lenses and veins. The former are 
wrapped about with somewhat scanty green biotite. There is some 
secondary epidote associated with the biotite. The slide has a clastic 
and gneissoid character. The quartz lenses represent fractured 
pebbles. 

On the road northwest from Oakwood, just north of Conowingo 

'For explanations of the more technical terms employed in the following descrip- 
tions see the glossary at the end of this chapter. 



114 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

Creek, and in a northeast-southwest line from this point, the mica- 
gneiss shows a conglomeratic phase. It is thoroughly crystalline and 
schistose, a rather fine-grained aggregate of muscovite, quartz and 
feldspar, with secondary chlorite and epidote. The traces of quartz 
and gneissic pebbles can be distinctly seen in the hand specimen. 
The slides show muscovite in considerable plates and also in minute 
scaly aggregates. There are rounded quartz and feldspar grains, 
these latter altered to muscovite. Green scaly biotite and muscovite 
are wrapped about these grains, making the gneissoid conglomeratic 
character very conspicuous in the slide. Rounded apatites are also 
present and more or less magnetite. The feldspar is both orthoclase 
and plagioclase, and in some slides, is in about equal proportion with 
the quartz, but never predominates. Epidote is an insignificant 
secondary constituent, more or less confined to cracks. 

!S"ot more than one-fourth of a mile northeast of Bald Friar, the 
rock shows the same constituents as at the locality just described, 
but is somewhat coarser grained. The microscope shows large plates 
of muscovite and yellowish brown biotite. The feldspar is orthoclase, 
microcline and andesine-labradorite, and about equals the quartz in 
amount. Rounded apatites are also present. 

The eastern area of mica-gneiss is represented by slides from only 
two localities: on Big Elk Creek, one and a half miles northwest of 
Appleton, and about one mile north of Eair Hill. At the former 
locality the rock is very micaceous and contains so much pegmatitic 
material in parallel planes that it resembles an impregnation gneiss. 
It is coarse-grained, and hand specimen and slides show much brown 
biotite, some muscovite, fresh quartz with little feldspar, or with 
feldspar equalling the quartz in amount. Both plagioclase and or- 
thoclase feldspar are present. The structure is thoroughly gneissic. 

At the latter locality quartz and feldspar bands alternate with the 
scales of brown biotite, which lie with their longer axes parallel to 
the banding. 

The mica-gneiss included within the granite-gneiss and outcropping 
on the Susquehanna river, is a fine-grained grey schistose rock. It 
is composed chiefly of quartz and mica. The mica is both biotite 



MARYLAND GEOLOGICAL SURVEY 115 

and muscovite. The former occurs in shreds or blades of a green 
color, which usually show a parallel grouping. It is sometimes re- 
placed by chlorite. The latter mica occurs both as blades and in 
aggregates of microscopic scales, forming bands in a mosaic of inter- 
locking quartz grains. In this fine-grained quartz mosaic are larger, 
rounded quartzes giving a clastic appearance to the section. 

Staurolite, garnet, tourmaline, zircon, apatite, rutile and magnetite 
are accessory constituents. Staurolite crystals may be found in the 
field most abundantly where Basin Eun has eroded the gneiss. They 
show, under the microscope, a complete change to an aggregate of 
microscopic muscovite scales. This is a not unusual alteration of 
staurolite and has been described elsewhere. 

The garnets are often partially or completely altered to an aggre- 
gate of chlorite scales. The alteration begins at the periphery and 
proceeds towards the interior. A central garnet core, therefore, 
remains where the alteration is still incomplete. The chlorite usually 
preserves the crystal form of the garnet, but this may be somewhat 
obscured by the growth of chlorite into the surrounding matrix. 
Garnet, tourmaline, and magnetite occur both in the gneiss and in 
the altered staurolite. Zircon and apatite are included in the quartz 
of the gneiss. Entile needles occur in the chlorite. This mineral 
is often a conspicuous secondary constituent. Epidote is rarely pres- 
ent as an alteration product. 

Analyses I and III, given below, are from this formation, as it 
occurs to the north in Fennsylvama and represent the general com- 
position of the mica-gneiss found in Cecil county. There have been 
tabulated with them an analysis of a biotite-gneiss from Freiberg, 
Saxony, two analyses of Canadian gneisses, and two analyses of slates, 
with which the gneisses may be compared. 

That, in general, the gneisses correspond in composition to the 
slates is plain. Analysis I represents a more silicious slate. The 
characteristics which these analyses have in common are the high 
percentage of alumina, the low percentage of the alkalies, and the 
preponderance of magnesia over lime. These' are characteristics 
common to silicious argillites. 



116 



THE CRYSTALLINE ROCKS OF CECIL COUNTY 



CHEMICAL ANALYSES OF MICA-GNEISS. 





I' 


II 


III 


IV 


V 


VI 


VII 


Si0 2 


66.13 


66.42 


60.33 


61.96 


57.66 


58 . 37 


• 14. 20 


Al a O s 


15.11 


14.76 


20 . 85 


lit. 73 


22.83 


21.99 


16.80 


Fe„0 3 
FeO 


2 5 2 

:;. L9 


7.50 


3.59 
4.47 


4.60 


7.74 


1 . 66 


4.2:; 


MgO 


2 . 42 


1.80 


2.07 


1.81 


3.56 


1 . 20 


3 . 04 


CaO 


1 .87 


2 22 


1 .82 


.35 


1.16 


.30 


.73 


Na.,0 


2.71 


1.75 


1 . 38 


.79 


.60 


trace 


:;.n7 


K.,0 


2.86 


3.52 


2.84 


2.50 


5 . 72 


1.93 


3.26 


H 2 + 
ILO- 


1.55 ) 
.24 f 


1.85 


2.78 


1.82 


1.50 


4.03 


3.42 


Ti0 2 


.82 




1.41 


1.66 




trace 




ZrO a 


no test 














co 2 


none 










.30 




P 2 5 


. 29 




.28 






.93 




s 


trace 










.11 




Cr 2 3 


none 














NiO 


trace 














MnO 


.22 






trace 


trace 


trace 




BaO 


j faint "» 

( trace | 














SrO 


none 














Li 2 


j faint ) 
( trace ) 














Total . . . . 


99.93 


99.82 


101.82 


99.55 


100.77 


00.01 


99.65 



I. — Sample material from several representative localities in Philadelphia belt of 
mica-gneiss. Analysis made by W. F. Hillebraud in the laboratory of the U. S. 
Geological Survey. 

II.— Biotite gneiss, Freiberg, Saxony. Described as containing orthoclase, plagio- 
clase, quartz, biotite, more or less muscovite, and apatite, rutile, zircon, tourmaline, 
garnet, hornblende and pyrite as accessory constituents. Zirkel, Lehrb. Petro., 
vol. iii, p. 223. 

III. — From exposure north of Jenkintown Junction and west side of Tacomy 
Creek. F. A. Genth, Jr., Analyst. Described as containing garnet, mica, feldspar 
and magnetite. Report C 6 ., p. 122. 

IV. — Gneiss from St. Jean de Matha, Province of Quebec. A quartzitic gneiss 
with orthoclase, garnet, sillimanite, graphite and pyrite. N. N. Evans of McGill 
University, Analyst. F. D. Adams, Amer. Jour. Sci., July 1895, p. 67. 

V. — Gneiss from the west shore of Trembling Lake, Province of Quebec. A bio- 
tite gneiss with quartz and orthoclase and bands of garnet and sillimanite. W. C. 
Adams of McGill University, Analyst. F. D. Adams, loc. cit. 

VI. — Peach Bottom roofing slate from Harford County. Booth, Garrett and Blair, 
Analysts. See Md. Geol. Surv., vol. ii, p. 226. 

VII. — Rooting slate (Cambrian) from Melbourne, Proviuce of Quebec. T. Sterrj 
Hunt, Analyst. Geology of Canada, 1st;:;, p. 600. 



linn oxides uncorrected for inlluence of sulphides or vanadium. 



maryland geological survey 117 

Granite-Gneiss. 
biotite-granite (quartz-monzonite) . 

The most acid type of the igneous intrusives occurring in large 
bodies is represented by the biotite-granite-gneiss of the Port Deposit 
and Frenchtown quarries. This type has received considerable atten- 
tion because of its economic importance. 

It is described and figured in Volume II of the Maryland Geological 
Survey (pp. 138-147), where Plate VIII reproduces the surface of a 
polished block, and Plate IX, Figure 1, shows the microstructure of 
the rock. 

The rock is of a light bluish white to grey color, mottled with irreg- 
ular, more or less disconnected and overlapping bands of dark biotite. 
It is this parallel grouping of the mica flakes that produces the gneis- 
soid structure which is so characteristic of the Port Deposit granite- 
gneiss. 

The original constituents of the rock are quartz, feldspar and bio- 
tite, with accessory constituents apatite, zircon, titanite, allanite, 
garnet, tourmaline and magnetite. Secondary constituents are mus- 
covite, hornblende, epidote, chlorite and occasionally calcite. Quartz 
and feldspar give the predominating light tone to the rock. There 
are considerable areas of the former mineral, which resolve them- 
selves under the microscope into aggregates of interlocking quartz 
grains. The granulated character and the freshness of the quartz 
offer a sharp contrast to the greatly altered but less granulated 
feldspar. The chemical simplicity and stability of the quartz pre- 
vents its adjustment to pressure by means of a new arrangement of 
the chemical molecules. The strain is relieved only by granulation 
and recrystallization. The feldspars, on the other hand, adjust them- 
selves to the zone of pressure not alone by granulation and twinning, 
but also by a new chemical combination. The chemical change 
involved in the production of the new mineral is slight, but the 
physical change is great. The mineral formed is muscovite. The 
production of this mineral, with its longest axis at right angles to 
the pressure, enables the rock to occupy much less space in the 
direction of pressure. 



118 THE CRYSTALI. IX 10 ROCKS OF CECIL COUNTY 

Undiilatory extinction, polysyntlietic twinning, the development 
of microcline and partial granulation are further pressure effects. 
Epidote is always present as an alteration product. It is sometimes 
very abundant, and in well-defined crystals. This mineral can hardly 
be considered a product of pure dynamic metamorphism. Its pro- 
duction seems to belong to a zone intermediate between the zones of 
metamorphism and of weathering. Like the products of the latter 
zone it contains water and leads to the more ready disintegration of 
the rock. While, like the products of the zone of metamorphism, it 
forms in response to pressure and at great depth. More than one 
species of feldspar is present. Orthoclase, which may show undiila- 
tory extinction or granulation, is most frequently altered to muscovite. 

Microcline is recognized by the characteristic gridiron structure. 
It may be somewhat granulated but is free from muscovitization. It 
represents a molecular rearrangement of orthoclase in response to 
pressure without an accompanying change in chemical composition. 

The predominating feldspar is plagioclastic and may constitute 
about a third of the rock. It is an acid plagioclase. The extinction 
angles place it between Ab 3 An x and Ab 2 An x , it accordingly corre- 
sponds to the oligoclase species. The feldspars often show a marked 
tendency towards idiomorphism, while zonal structure is common, 
though somewhat obscured by the alteration products. 

CHEMICAL COMPOSITION. 

The following chemical analysis of the Port Deposit granite was 

made for Dr. Grimsley by the late Wm. Bromwell, of Port Deposit, 

at the laboratory of the Johns Hopkins University. 

Si0 2 73.69 

A1,0, 12.89 

i-v ,,<>., l.oa 

FeO 2.58 

MgO 50 

CaO :>.T4 

Na a O 2.81 

K,0 1.48 

II ,<) 1.06 

Total 99.77 



MARYLAND GEOLOGICAL SURVEY 119 

Disregarding the secondary constituents, the chief primary con- 
stituents may be calculated as follows: 



...34.86 



Quartz 42.28 Orthoclase 8.91 

Orthoclase 8.91 Oligoclase, 

Albite 23.71 Ab 2 An,, appr. \ 

Anorthite 11.15 

Biotite 10.41 

Misc. \ Ma ^ite ) g ^ Feldspar 43.77 

( Apatite . . ) 



Total 99.62 

The predominance of plagioclase over orthoclase places the granite 
with the quartz-monzonite type. 

The term quartz-monzonite, as originally defined, covered only 
those quartz-bearing acid plutonics exhibiting an equal development 
of orthoclase and plagioclase. Present usage, however, gives a wider 
signification to the monzonite. Grano-diorite has been proposed to 
designate those plutonics intermediate between quartz-monzonites 
and diorites whenever plagioclase is more abundant than orthoclase. 
It has seemed advisable to the writer to use monzonite in its wider 
significance. 

HORNBLENDE-BIOTITE-GRAS"ITE (QUARTZ-MONZONITE) . 

In the vicinity of the more basic igneous formation to the north, 
the biotite-granite becomes darker colored and less gneissoid. This 
is due to the development of hornblende, which is here the predomi- 
nating ferromagnesian constituent. 

This facies of the granite forms a narrow zone, nowhere exceeding 
a mile in width, between the biotite-granite and the quartz-hornblende- 
biotite-gabbro. The type is exposed in the neighborhood of Harris- 
ville, at the crossroads two miles west of that hamlet, and southwest 
of Porter Bridge. 

On the southeastern border of the granite body, a hornblende- 
granite is also developed. This is typically exposed on Principio 
Creek, in the neighborhood of Principio Furnace, on Northeast Creek, 
near Northeast Tillage, and on the lower courses of Big Elk and 
Little Elk creeks. Feldspar, quartz, hornblende and biotite are the 
essential constituents and can be distinguished in the hand specimen. 



120 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

Magnetite, apatite, zircon and titanite are accessory, and garnet, 
epidote, chlorite, calcite and muscovite, secondary constituents. 

The feldspar varies from a very subordinate amount to nearly 45 
per cent of the rock. It is both orthoclase and oligoclase (Ab 3 An^. 
There is about double the amount of the latter. This feldspar shows 
extended alteration into epidote, which forms crowded aggregates 
of well-defined crystals or large irregular areas. 

An analysis of the rock from Rowlandsville gives a larger per- 
centage of lime than the oligoclase, determined by optical measure- 
ments, demands. This excess of lime and the widespread epidoti- 
zation suggests the addition to the rock of lime from external sources. 

Quartz varies considerably in amount and may constitute as much 
as 33 per cent of the rock. It is the normal granitic quartz. Partial 
or complete granulation has affected it in many cases. 

Biotite and hornblende may be present in nearly equal amounts 
in this type, or either one may partially replace the other. Biotite 
is the usual deep brown pleochroic variety. 

Hornblende is a compact green varity, showing under the micro- 
scope the deep blue green, olive green and light yellowish green axial 
colors. In the more gneissoid granite it occurs in slender prismatic 
crystals without terminal planes. It also occurs in broadly prismatic 
forms exhibiting no pressure arrangement. 

CHEMICAL COMPOSITION. 

SiO„ 66.68 RECALCULATION. 



A1 2 3 14.03 

Fe 2 O s 1.58 

FeO 3.23 

Mir<> 2.10 

< !aO 4.80 



Quartz 33.82 

Orthoclase 12.26 

Albite molecule 22. 15 

Anorthite molecule 7.80 

Biotite 17.83 



Magnetite 2.30 

Titanite 1.20 

Misc 3.20 



Na a O 2.65 

k 2 o 2.05 „ p _ ® ;: • • ..:; 

IT 2 () + 1.00 

H 2 — 10 

TiO 50 

P,0, 10 

MnO 10 

BaO os 

SrO trace 

Li.O trace 



100.70 



100.23 



1 Analysis made by W. F. Hillebrand in the laboratory of the U. S. Geol. Surv. 
Grimsley, loc. til., pp. 88-so. 



MARYLAND GEOLOGICAL SURVEY 121 

The above is an analysis of a basic granite collected from this belt 
by G. P. Grimsley, who describes it as a biotite-granite, " containing 
an abundance of idiomorphic plagioclase crystals, with zonal arrange- 
ment of epidote, considerable unstriated feldspar, which also contains 
epidote and abundant quartz." 

A recalculation of the analysis was made in the light of this descrip- 
tion. The plagioclase feldspar was given the composition of Ab 3 An x 
which is about the composition of the feldspar of the slides from this 
belt examined by the writer. 

This recalculation probably gives too high a percentage of quartz, 
as some of the silica is combined with the lime, of which there is a 
considerable percentage (2.86) remaining after the calculation of 
the anorthite, apatite and titanite. It is believed that lime and silica 
have been added to the rock by percolating water, thus assisting in 
the general epidotization of the rock. 

The reduction of the potash feldspar and the predominance of the 
lime-soda feldspar, places this " granite " also with the quartz-mon- 
zonites. 

Gabbro. 

meta-gabbro or quartz-hornblende-gabbro and hornblende- 

GABBRO. 

The belt of basic igneous material immediately to the north of the 
quartz-monzonite, is in the main a norite and hypersthene-gabbro, 
with a quartz-hornblende-gabbro facies along the granite contact. 

About one mile below Conowingo Station on the Susquehanna 
river, a blue quartz is somewhat abruptly and conspicuously developed 
in the gabbro. This is associated with the presence of hornblende. 
The rock thus has the aspect of a quartz-diorite, and was described as 
such by Dr. Leonard. Optical and chemical determinations show 
that the feldspar remains, as in the norite and gabbro, a labradorite- 
bytownite. This facies, therefore, still belongs in the gabbro family. 
The hornblende often shows itself, by its relation to a pyroxenic core, 
to be of a secondary character. 

The type is well exposed on the Susquehanna river, in the neigh- 
borhood of Porter Bridge and on the left bank of Octoraro Creek, 
near its junction with Stone Run. 



L22 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

Tt is difficult to separate in the field the qiiartz-hornblende-gabbro 
and the qiiartz-hornblende-monzonite. The separation is based en- 
tirely on the character of the feldspar, which can only be ascertained 
through optical or chemical determinations. The boundary given 
upon the map is believed to be approximately correct. 

Hornblende-gabbro which usually, and perhaps always, represents 
the alteration of a pyroxene gabbro (meta-gabbro), occurs in the 
quartz-hornblende-gabbro belt, in all the dikes from the gabbro body 
and wherever the norite or hypersthene has been subjected to 
pressure. 

The quartz-hornblende-gabbros and the hornblende-gabbros are of 
about the same grain as the quartz-monzonites, but the contrasting 
dark green hornblende and opaque white or light grey feldspar pro- 
duce a more conspicuously mottled effect in the former types than is 
characteristic of the latter. Feldspar, hornblende and, in a large 
proportion of these rocks, quartz are the essential constituents and are 
readily distinguished in the hand specimen. 

The usual accessories magnetite, apatite, zircon and titanite are 
present. Epidote and chlorite are abundant as alteration products. 

The feldspar of the hornblende-gabbro is, for the most part, by- 
townite. Orthoclase is sometimes altogether absent and sometimes 
scantily present. 

Dr. Leonard's determinations, based on stauroscopic measurement 
of extinction angles on 001 and 010, give approximately the compo- 
sition of Abi An 4 to the bytownite. That, however, a bytownite 
with the composition Ab x An 6 is also present, is indicated by some of 
the writer's measurements. Specific gravity determinations, by 
means of the Thoulet solution, by Dr. Leonard, gave 2.71 and 2.72 
for fresh fragments of feldspar. 

The feldspar of the quartz-homblende-biotite-gabbro is evidently 
a more acid variety, a labradorite of the composition Abj An^ 
Optical determinations and analyses both indicate this to be the case. 

The very general alteration which the feldspar has undergone is an 
epidotization and a zoisitization. The epidote is singularly free from 
the greenish yellow tone which usually marks it, and the close aggre- 



MARYLAND GEOLOGICAL SURVEY 123 

gation of epidote and zoisite crystals, in which the complete alteration 
results, is the cause of the opaque white character which the feldspar 
so generally possesses. The periphery of the feldspar crystal is often 
left more or less free from the epidote grains. The proportion of 
feldspar varies considerably, but rarely exceeds two-fifths of the rock. 

Hornblende always exceeds the biotite and both together nearly 
equal the feldspar. It is the green compact variety. The prismatic 
zone is usually well developed, giving rise to columnar forms. Con- 
fused aggregates and imperfectly developed individuals are also usual. 
Twinning is not uncommon. The pronounced pleochroism is of the 
type peculiar to green hornblende. 

Magnetite, apatite and quartz may be included in the hornblende. 
Chlorite is its alteration product and is commonly but not extensively 
developed. 

Biotite is sometimes present in these gabbros. Its presence is 
associated with a proximity to the biotite-bearing quartz-monzonites. 
Like the hornblende it alters to chlorite. 

Quartz, when present, may constitute a fifth of the rock. It is 
conspicuous in the hand specimen where it possesses a genuinely blue 
color. It exhibits no variation from granitic quartz. 

Pressure effects are apparent both in the hand specimens and slides, 
but only locally and in a, very limited way, is anything approaching a 
schist produced. 

Epidotization and zoisitization are the most marked metamorphic 
changes and seem to be a result both of dynamic action and of pro- 
cesses of weathering. 

There is a considerable increase in the acidity of the feldspar in the 
quartz-bearing gabbros, from Ab x An 4 to Abi An x . The feldspar 
remains a labradorite, and the rock is still of the gabbro type and not 
a diorite. 

Orthoclase was an accessory constituent in all the slides examined 
by the writer. It is probable, however, that some of the potassa 
should be referred to the albite molecule, thus reducing slightly the 
percentage of orthoclase. 



124 



THE CRYSTALLINE ROCKS OF CECIL COUNTY 



CHEMICAL COMPOSITION. 

I. II. III. 

Si0 2 58.57 55.16 44.04 

Al 2 O a 16.10 17.51 20.01 

Fe 2 3 2.89 2.62 4.22 > 

FeO 6.12 5.83 8.61 

MgO 3.33 4.35 5.01 

CaO 7.30 8.50 11.68 

Na 2 2.11 1.83 1.24 

K 2 6 1.01 1.08 .15 

H 2 + 1.27 2.01 1.00 

H 2 0- 21 .21 .11 

C0 2 none none none 

TiO„ 1.41 .64 2.24 

Zr(X.... 09 .02 .10 

P 2 6 37 .21 .52 

P0 3 undet. nudet. undet. 

CI none " " 

F undet. " " 

FeS 2 2 trace .03 3 (.02 S.) .25 (.135 S.) 

Cr 2 3 none trace none 

NiO CoO " .01 .01 

MnO 18 .15 .28 

BaO trace trace none 

SrO 

Li„() " " trace 

V 2 3 02 (.018) .04 (.036) .05 (.053) 

Total 100.07 100.17 100.42 

I. — Quartz-biotite-hornblende-gabbro. Near the Foundry on Stone Run. 

II. — Quartz-biotite-hornblende-gabbro. Near Porter Bridge on Octoraro Creek. 

III. — Hornblende-gabbro. Stone Run, % mile northwest of Rising Sun. 

Analyses made by W. F. Hillebrand in the laboratory of the United States 
Geological Survey. Amer. Geol., vol. xxviii, p. 146. 

RECALCULATION OF ANALYSES! 



Quartz 

Orthoclase 

Albite molecule 

Anorthite molecule 

Hornblende 

Biotite 

Magnetite 

Apatite 

Misc 



I. 


II. 


III. 


21.56 


10.33 


1.39 


6.12 


6.42 


.89 


17.00 


15.76 


10.53 


18.96 


16.73 


44.01 


19.76 


27.05 


30.79 


8.70 


18.61 


8.33 


4. is 


3.77 


•»8.33 5 


.81 


.45 


1.14 


1.91 


1.10 


2.70 



'.10. 90 



loo.:.' 



100.38 



1 Subject to correction for influence of possible pyrrliotite. 

-Sulphur calculated as FeS 2 , but exists as pyrrhotite or other sulphides soluble 
in HC1. 

; Perhaps mainly pyrrhotite. 

4 Titaniferons. 

5 Tlie percentage of magnetite is probably unduly large because of the uncorrected 
ferric oxide percentage. 



MARYLAND GEOLOGICAL SURVEY 125 

NORITE AND HYPERSTHENE-GABBRO. 

The prevalent type of the gabbroitic belt is a norite. This type is 
associated with a hypersthene-gabbro. Neither type is confined to 
any particular portion of the region, and the latter may be considered 
a mineralogical facies of the norite. 

Possessing the same constituents, structures and alteration pro- 
ducts, they differ petrographically only in the presence in the latter 
type of a monoclinic pyroxene in about equal proportions with the 
orthorhombic pyroxene. They will not be separated in the petro- 
graphic discussion. 

Good outcrops of the norite and of the hypersthene-gabbro are 
found on the Susquehanna river, while boulders of both types strew 
the country throughout the gabbroitic belt. The rock is not usually 
as coarse-grained as the hornblende-gabbro, nor does it exhibit the 
mottled character of the hornblende-gabbro, but is of a more uni- 
formly dark tone, often possessing a bronzy or purplish tinge. The 
shade varies from a light tint where the rock is rich in feldspar to a 
dark tint where the rock is so poor in feldspar as to be almost a pyrox- 
enite. Both types are remarkably fresh. 

A reddish-brown hypersthene and glossy grey feldspar are essential 
constituents easily distinguished in the hand specimen. A monoclinic 
pyroxene, diallage or augite, is an accessory constituent in the norite, 
and partially replaces the hypersthene in the hypersthene-gabbro. 
A porphyritic norite, with phenocrysts of diallage, 13 mm. in length, 
imbedded in a hypersthene-plagioclase groundmass, has been reported 
from the vicinity of Mt. Hope Church, one mile southwest of Sylmar. 

The accessory constituents are magnetite, apatite, quartz and rarely 
olivine. Magnetite is less abundant than is usually the case in 
gabbroitic rocks. The secondary constituents are hornblende, epi- 
dote, zoisite, albite, and chlorite. 

The feldspathic constituent is again bytownite. Practically the 
same extinction angles were found on the basal and clinopinacoidal 
planes as in the case of the bytownite of the hornblende-gabbros. 
Dr. Leonard reports the specific gravity as 2.74, showing that the 
feldspar may range somewhat lower in basicity. The proportion of 



126 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

feldspar present varies widely, from nearly zero in certain facies to 
more than 50 per cent of the rock in the normal type. It is gabbro- 
itic in the manner of its occurrence, in broad, irregular areas, seldom 
exhibiting crystal boundaries. Both in the norites and in the hyper- 
sthene-gabbro the feldspar is often saussuritized. This change is 
associated with the passage of the pyroxene, whether monoclinic or 
orthorhombic, into hornblende. Chlorite is a less common alteration 
product of the feldspar. 

The pyroxenic constituent is sometimes wholly an orthorhombic 
variety hypersthene. This mineral possesses the usual gabbroitic 
allotrirnorphic character, and exhibits the brilliant trichroism and 
optical orientation of hypersthene. 

A monoclinic pyroxene, with a pinacoidal parting in addition to 
the prismatic cleavage, usually accompanies the hypersthene and 
is, in the hypersthene-gabbro, nearly equal or more rarely predomi- 
nating in amount. 

Pyroxene, like the feldspar, varies in proportion. It is rarely less 
than two-fifths of the rock in which it occurs and may constitute a 
much larger percentage. 

Hornblende and chlorite are its alteration products. The former 
mineral sometimes entirely replaces the pyroxene. 

Quartz is an original constituent of the norite as of the hornblende- 
gabbro, but is much more rarely found. 

Olivine is also rarely found. It occurs in a hypersthene-gabbro 
associated with poridotite, one-quarter of a mile north of Harrisville, 
near Oak Grove schoolhouse. 

Olivine, whenever it comes in contact with the feldspar (bytown- 
ite), is surrounded by a double reactionary rim. The inner border 
is composed of a colorless highly polarizing mineral with a consider- 
, able index of refraction. The outer border is rendered almost 
opaque by the close aggregation of a green, fibrous mineral. The 
index of refraction and the polarization colors are high in this case 
also. 



MARYLAND GEOLOGICAL SURVEY 127 

The mineral of this outer border possesses all the characteristics of 
adjacent, easily determined hornblende, except that of the hornblende 
cleavage, which the form of the mineral renders impossible. There 
seems little doubt that the outer border is hornblende. On its inner 
edge it becomes colorless and resembles the transparent constituents 
of the inner zone. This inner zone is probably tremolite. The altera- 
tion of olivine to tremolite and actinolitic hornblende is not uncom- 
mon and has been frequently described. It has been considered a 
niagmatic reaction rather than the result of dynamic metamorphism, 
subsequent to the consolidation of the rock. There seems to be no 
convincing proof on this point. 

The pyroxene of this olivine-gabbro is partially altered to horn- 
blende, the result of a reaction between the ferromagnesian silicate 
and the lime-silicate. The feldspar shows some alteration to epidote, 
but is, for the most part, quite fresh. 

The alteration of the norites and hypersthene-gabbro has resulted 
in the formation of a hornblende-saussurite rock, producing in the 
hand specimen a mottled white and green aspect. Rarely has the 
rock been subjected to such pressure as to produce a schistose struc- 
ture. In this case chlorite has been largely developed as well as 
uralite. Such schistose gabbro is exposed on the right bank of the 
Octoraro at the bridge, one mile south of the State boundary. 

The following analysis represents a single specimen of the norite. 
It will be seen that the feldspar is even more basic than is usual for 
this type. The slide shows the emergence of an axis on 010, with an 
extinction of — 37°, and an extinction on 001 of — 33°, — 36°, 
— 37°. The feldspar was accordingly given the composition of 
Abi An 12 . With this composition for the feldspar, the alumina and 
lime percentages accord, and the above results are obtained by 
recalculation. 

The slide also shows an alteration of the hypersthene to hornblende. 
This change always takes place at the expense of the feldspar from 
which the lime is obtained. 



128 



THE CRYSTALLINE ROCKS OF CECIL COUNTY 



CHEMICAL COMPOSITION. 



ISTorite, three-quarters of a mile northwest of McKinseys Mill. 



Si0 2 4S.02 

ai 2 o 3 20.01 

Fe 2 3 1.115' 

FeO 7.29 1 

MgO 10.05 

CaO 11.42 

Na 2 51 

K a O 05 

H 2 + 57 

HoO - 10 

C0 2 25 

Ti0 2 23 

Zr0 2 none 

P 2 5 trace 

S0 3 undet. 

CI « 

F « 

FeS 2 2 3.11 ( .06 S.) 

Cr 2 3 03 

NiO, CoO 01 

MnO 18 

BaO none 

SrO « 

Li 2 trace 

V„0, 02 



RECALCULATION 

Orthoclase 


OF 


ANALYSIS. 
28 


Albite molecn 


le 
[ecu 




4.35 

. 52 '.t7 


Hypersthene 
Magnetite . . . 


39.70 

1.63 


















Total 


100.25 



Total 99.98 

Made by W. F. Hillebrand of the U. S. Geol. Survey. Amer. Geol., 
vol. xxviii, pp. 151-152. 

THE SOUTHERN GABBRO BELT. 

Grays Hill, east of Elkton, Chestnut Hill and Iron Hill in Dela- 
ware, and two outlying exposures, one on the Pennsylvania railroad, 
throe-fourths of a mile south of Iron Hill station, the other on the left 
bank of Big Elk Creek, two miles north of Elkton, exhibit olivine- 
and hypersthene-gabbro, pyroxenites, peridotites and serpentine. 



1 Subject to correction for influence of possible pyrrhotite. 

'Sulphur calculated as FeS 2 , but exists as pyrrhotite or other sulphide soluble 
in IIC1. 

:t Perhaps mainly pyrrhotite. 



MARYLAND GEOLOGICAL SURVEY 129 

These types do not admit of separate mapping. The pyroxenites 
and peridotites are facies of the gabbro and the serpentine is a local 
alteration product. 

The gabbro of this belt is both medium grained and coarse grained; 
grey when fresh, green when uralitized, and a rusty brown on the 
weather surface. A nodular weathering is also very marked in 
the gabbro boulders strewing the meadows between Grays Hill and 
Iron Hill station. The nodules are somewhat ellipsoidal in form, 
3 x 3^-5 inches in diameter. The uralitization of the pyroxene on 
the periphery of these nodules assists in their easy separation from the 
rock. The nodules do not possess a concentric or radiate structure, 
but are a product of spheroidal weathering on a small scale. 

The essential constituents are feldspar, pyroxene and olivine; the 
accessories are magnetite and apatite; and the secondary constituents 
are hornblende, tremolite, epidote and serpentine. The feldspathic 
constituent is both a basic bytownite (Abi An 5 ) and an anorthite (Abi 
An 12 ). 

The feldspar of the Iron Hill gabbro, a continuation into Delaware 
of the Grays Hill areas, was isolated and analyzed for Professor 
Chester * by Mr. Riggs. The specific gravity ran as high as 2.749. 
The anaysis is as follows: 

IRON HILL FELDSPAR. THEORETICAL COMP. 

Of At^AU;.,. 

Si0 2 44.09 44.87 

A1 2 3 35.41 35.66 

Fe 2 3 51 

(FeO not det.) 

MnO trace .... 

CaO 18.47 18.61 

MgO none .... 

Na 2 99 .86 

K 2 19 

Loss on ignition 35 .... 

Total 100.01 100.00 

The feldspar, as a rule, is very fresh. Where alteration has taken 
place the product is epidote. The proportion of feldspar varies from 
nil to somewhat more than half the rock. 

' Bull. U. S. Geol. Survey, No. 59, Washington, 1890, p. 28. 



130 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

The pyroxenic constituents are hypersthene and diallage. Both 
varieties may be present, or either one to the exclusion of the other. 
While they are sometimes quite fresh, more generally some stage 
of alteration is observable. The uniform alteration product is green 
hornblende. In the case of orthorhombic pyroxene the alteration is 
always peripheral, while with monoclinic pyroxene it takes place 
within the body of the mineral as well as on the surface. 

This difference is due, of course, to the respective compositions 
of the two pyroxenes. The change of hypersthene to hornblende 
must be a reaction between the ferro-magnesian silicate and the sur- 
rounding feldspar, which furnishes the lime for the hornblende. 

In the case of the augite, on the other hand, the process is a true 
epimorphism, and the alteration to hornblende is also always a direct 
one. The alteration of hypersthene to hornblende may be direct or 
through the intervention of tremolite. This mineral forms an inner 
colorless zone between the hypersthene and the hornblende. 

The pyroxene-hornblende epimorphism in the Iron Hill gabbros 
has been accurately described by Professor Chester, 1 who reports the 
process of change of hypersthene to hornblende as always an indirect 
one. Additional material from this region shows that a direct change 
from hypersthene to hornblende may take place without the inter- 
vention of tremolite. 

This pyroxene-hornblende alteration may be seen in all stages of 
progress. When the last stage is reached a hornblende-feldspar rock 
results, which is a not infrequent type in this area. This facies 
represents a true meta-gabbro rather than a hornblende-gabbro, in 
which the hornblende is original. 

The character of the feldspar also distinctly separates these horn- 
blendic facies from the diorite, with which they have ordinarily been 
classed. 

Pyroxene varies in proportion from slightly less than 50 per cent, 
to 100 per cent of the rock. In the latter case the rock becomes a 
pyroxenite of the hypersthenite or websterite type. 

'Bulletin U. S. Geol. Surv., No. 59, pp. •.': , ,-:J7. 



MARYLAND GEOLOGICAL SURVEY 13.1 

Olivine is infrequently a constituent of these hypersthene-gabbros. 
It is interesting in showing the same alteration products as the hyper- 
sthene. A double reactionary rim surrounds the olivine wherever 
it is in contact with the feldspar. The inner zone is colorless and 
the outer zone composed of closely crowded very light green fibres. 
Tremolite and hornblende, it is thought, are the two minerals repre- 
sented. The constituents of the rim are too minute for accurate 
optical determination, but index of refraction, double refraction, 
color and association are those of the above minerals. 

Much magnetite and some serpentine are also developed along the 
cracks which thoroughly penetrate the olivine. 

That serpentine, associated with the liberation and secondary de- 
posit of silica and iron oxides, is a final product of alteration of these 
olivinitic rocks, is believed to be the case because of the association 
with the latter of serpentine, of limonitic opal, and of silicious limonite 
and hematite ores. The serpentine shows the grating structure and 
contains some tremolite, magnetite and quartz, together with an 
abundance of hematite, limonite, opal and cryptocrystalline silica. 
The latter group of minerals may entirely replace the serpentine. 

Typical hypers tbene-gabbro showing the pyroxenes altering to 
hornblende occurs in Grays Hill and in the meadows between Grays 
Hill and Iron Hill Station. 

Olivine-hypersthene-gabbro is exposed on the hill in the woods 
south of the crossing of the road to Iron Hill Station by the Penn- 
sylvania railroad. A typical meta-gabbro is exposed in the Penn- 
sylvania railroad cut just southwest of this crossing and in boulders 
along the eastern base of Grays Hill. Pyroxenite facies were not 
found within the Maryland boundary. Serpentine and limonitic 
opal are exposed in the railway cut mentioned, and on Mr. Jackson's 
farm, on the left bank of Big Elk Creek, two miles north of Elkton. 

These gabbros are undoubtedly related genetically with the gabbro 
belt to the north. They are as basic as the most basic type of that 
belt. Throughout this southern area quartz is absent and the feld- 
spar is bytownite-anorthite. These basic gabbros pass northeastward 
into the acid quartz-bearing Brandywine gabbros, which cover large 
areas in Delaware and Pennsylvania. 



132 the crystalline rocks of cecil county 

Non-Feldspathic Rocks, 
pyroxenite. 

This type of rock, into which the gabbro readily passes by a 
decrease in the amount of feldspar, is more or less prevalent along 
the border of the serpentine and also appears as dikes in the gabbro 
belt. 

The rocks of this type are somewhat coarse-grained aggregates of 
hypersthene and diallage. The former mineral is reddish brown in 
the hand specimen and the latter greenish black. These two con- 
stituents may be present in about equal proportions, or a decrease in 
the amount of one or the other pyroxene converts the rock into a 
diallagite or a hypersthenite. 

Neither of these constituents differs in any particular from the 
hypersthene or diallage of the hypersthene-gabbro and norite. 

Prismatic cleavage and the parting parallel to go P go (100) are 
very marked features of the diallage. Magnetite and sometimes 
scanty feldspar are accessory constituents. 

The pyroxenites readily alter to smaragdite, anthophyllite, tremo- 
lite, and other fibrous amphiboles. Pyroxenites, partially altered 
to amphibolites, and amphibolites in which the alteration is complete, 
are very common along the serpentine border. The alteration may 
go further, converting the amphibolite into serpentine, and there is 
every reason to suppose that pyroxenites as well as peridotites are 
the source of the serpentines. 

The pyroxenite dikes south of Conowingo show alteration to fibrous 
amphibole. 

Fresh pyroxenite (hypersthenite) may be found in the vicinity of 
Oakwood, where it forms a facies of the norite, and south of Cono- 
wingo, where it occurs as a dike. 

Pyroxenite (websterite) is also found one and a half miles west of 
Sylmar, near the State line. 



MARYLAND GEOLOGICAL SURVEY 133 



CHEMICAL COMPOSITION. 

Pyroxenite (websterite) from Oakwood. 



RECALCULATION. 

Hypersthene 43.72 

Diallage 55.97 

Misc 79 



Si0 2 53.21 

A1 2 3 1.94 

Fe 2 3 1.44 

FeO 7.92 

MgO 20.78 

CaO 13.12 100.48 

Na 2 11 

K 2 07 

H 2 + 87 

H 2 0- 14 

C0 2 10 

Ti0 2 26 

Zr0. 2 trace 

P 2 5 " « 

CI., F uudet. 

FeS 2 i 03 (.02 S.) 2 

Cr 2 3 20 

NiO, Co O 03 

MnO 22 

BaO none 

SrO 

Li 2 trace 

V 2 3 03 



Total 100.47 

Analysis made by W. F. Hillebrand, of the United States Geological Survey. 
Arner. Geol., vol. xxviii, 1901, p. 159. 

The specimen that was analyzed was a fresh websterite, containing 
only hypersthene and diallage. 

The recalculation shows the relative proportions of these con- 
stituents. 

PERIDOTITE. 

This type is, like the pyroxenite, found associated with the serpen- 
tine, and as included bodies and dikes within the gabbro belt. 

The largest body, one mile southwest of Sylmar, exposes a peri- 
dotite largely altered to serpentine. One and one-half miles north 
of Harrisville, there occurs another area of peridotite. 

1 Sulphur is calculated as FeS.,, but exists as pyrrhotite or other sulphide soluble 
in HC1. 

2 Perhaps mainly pyrrhotite. 



134 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

Three-eighths of a mile southeast of Conowingo Station, on the 
Susquehanna river, there are three pyroxenite dikes and four that 
originally were peridotite. The latter are more or less completely 
altered to soapstone. They vary in width from twenty to forty feet 
approximately and strike northeast. The peridotites are more uni- 
formly coarse-grained than the material which has thus far been 
discussed. They are dark brownish green to black in color, and 
sometimes exhibit the characteristic lustre-mottling, due to the inter- 
ruption of a lustrous cleavage surface of pyroxene by dull grains of 
included olivine. 

The constituents are hypersthene, dial] age and olivine. Feldspar 
is an occasional accessory. Serpentine, tremolite, steatite and mag- 
netite are secondary products. 

Olivine is the oldest constituent and occurs as included crystals 
in the pyroxenes, or is the predominating mineral. It is always more 
or less altered to serpentine with the liberation of iron oxides. The 
pyroxenes are less likely to be altered, but tremolite, serpentine and 
steatite have in some cases formed at the expense of the pyroxene. 
As in the case of olivine-f ree rocks, either the orthorhombic or mono- 
clinic pyroxene may predominate, thus giving rise to two varieties 
of peridotite, the hypersthene-olivine rock or harzbergite, and the 
diallage-olivine rock or wehrlite. 

The association of the peridotites and pyroxenites with the ser- 
pentines and soapstones, and the more or less complete serpentini- 
zation of well recognized peridotites and pyroxenites, are presump- 
tive evidences that both types were once far more extended but are 
now represented by the serpentine. 

SERPENTINE. 

The great range in color and texture of the serpentine and asso- 
ciated material has already been presented. Every variety and shade 
of green characterizes them. The texture may be earthy, fibrous or 
massive. 

Massive serpentines more generally disclose a peridotitic origin, 
but even the earthy serpentines show remnants of original olivine. 



MARYLAND GEOLOGICAL SURVEY 135 

The fibrous serpentines exhibit remnants of tremolite and other 
fibrous anrphiboles by means of which their origin can be traced to 
pyroxenites. 

Serpentine possesses a more uniform appearance under the micro- 
scope than in the hand specimen. Faintly green, transparent sections, 
showing in polarized light a confusedly fibrous character and mesh 
structure, with olivinitic cores and an occasional crystal of pyroxene 
or tremolite, are a common type of earthy or massive serpentine. 

Chromic iron, magnetite, talc, calcite and quartz are accessory 
and secondary constituents. 

A preponderance of tremolite, anthophyllite or smaragdite char- 
acterizes the fibrous serpentines. Tremolite may still show a central 
area or core of pyroxene. 

Talc is a common secondary product both in the fibrous and massive 
serpentines. It may completely replace both serpentine and amphi- 
bole, converting the rock into a soapstone or a steatite-schist. 

The change to talc of the fibrous amphiboles is accompanied by 
the separation of calcite or dolomite which fills the interstices of the 
talc. 

A typical example of a calcareous soapstone is found in an exposure 
on the Octoraro Creek on the southern edge of the State line serpen- 
tines. It is a light colored bluish green, somewhat soapy rock, but 
rendered harder and less soapy than it would otherwise be by the 
presence of a magnesian calcium carbonate. Steatite and dolomite 
are the constituents. 

The origin of serpentine and soapstone from pyroxenites and peri- 
dotites is a well recognized fact, and the occurrence of serpentines 
with such a genesis from localities in Pennsylvania l and elsewhere 
has been described. 

Dike Rocks. 

It has been stated (p. 92) that, beside the ultra-basic dikes in the 
vicinity of Conowingo, which have been described, there occur in the 
crystalline formations of the county numerous acid and basic dikes, 
varying in width from one foot to a mile and a half. 

!Bull. U. S. Geol. Survey, No. 59, Washington, 1890. 



136 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

These intrusives are, for the most part, confined to the granite- 
gneiss and are exposed on the Susquehanna between Port Deposit and 
Frenchtown. 

Their location, extent, strike and field characteristics have been 
discussed (pp. 97-101). Their petrographic characters will now be 
presented. 

META-EHYOLITE. 

The most considerable and important of these later intrusives is the 
fine-grained acid formation which has so extended an exposure in the 
neigh borhood of Bay View and on Principio Creek. The true char- 
acter of the rock is obscured by the secondary development and 
growth of hornblende, epidote and chlorite. These minerals give 
a greener color, a less aphanitic aspect and a greater softness than is 
exhibited by the fresh material. The fresh rock, on the other hand, 
is of a greenish grey color, of very hard aphanitic character, and 
possesses inconspicuous quartz and feldspar phenocrysts. 

Its prevailing green aspect has led geologists to class it with the 
basic types. It was mapped as a gabbro by Professor Williams and as 
a diorite by Dr. Grimsley. 

Examination of thin sections of the French town exposures led Dr. 
Grimsley to classify the rock as a homblende-quartz-diorite and a 
biotite-hornblende-quartz-diorite. He adds that there is " nothing 
in their mineralogical composition opposed to the hypothesis that 
they are dynamically metamorphosed gabbros." He does not state 
the character of the feldspar upon which the classification of the rock 
must depend. It will be seen that the acidity of the feldspar excludes 
this rock from either the gabbro or diorite groups. 

The essential constituents are quartz, feldspar, biotite, hornblende; 
the accessory constituents are magnetite, apatite, titanite, garnet, 
pyrrhotite, muscovite; the secondary constituents are hornblende, 
epidote and chlorite. 

Slides from the fresher material show T a fine-grained quartz-feldspar 
mosaic with scattering quartz and feldspar phenocrysts, and blades 
of biotite, or of green hornblende and garnets and magnetite. The 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XI. 




FIG. 3.-GILPIN ROCKS (mETA-RHYOLITE), NEAR BAY VIEW. 




FIG. 2.— FALLS OVER GILPIN ROCKS, NEAR HAY VIEW, 



VIEWS OF PIEDMONT PLATEAU. 



MARYLAND GEOLOGICAL SURVEY 137 

hornblende rapidly increases in amount upon the periphery of the 
dike and in all altered material. 

The quartz-feldspar mosaic seems to be an original feature and not 
due to the complete crushing of the constituent of an originally 
coai se-grained rock, as premised by Dr. Grimsley. 

A proof of this lies in the presence of uncrushed phenocrysts, some- 
times with sharp crystal boundaries, which possess inclusions of the 
fine mosaic of the groundmass. 

Quartz constitutes a considerable proportion of the rock; not far 
from forty per cent when the rock is fresh. 

Feldspar is somewhat less in amount. It is rarely twinned and 
is without crystal boundaries. As a constituent of the groundmass, 
it is too fine-grained for determination. So far as the small, imper- 
fect and scattering phenocrysts admitted of determination, orthoclase, 
albite and an acid oligoclase are the species represented. Biotite 
occurs in numerous brown plates. It decreases in amount with the 
appearance of hornblende and disappears altogether with an excess 
of that constituent. Hornblende appears as sheaves of acicular green 
or nearly colorless crystals, or as minute acicular crystals, distributed 
with uniformity and parallelism, and constituting the prevailing con- 
stituent of the rock, or as broad green blades, also showing a parallel 
arrangement. 

Along the periphery of the dike, as exposed on the Susquehanna, 
an excess of hornblende is developed in the rock. It is of an acicular 
character, passing, toward the center of the dike, into the sheaf-like 
aggregates. 

Where widespread alteration has occurred, as is the case in all the 
exposures northeast of the gorge of the Susquehanna, notably at 
Blythedale and Bay View, hornblende is the prevailing constituent, 
or hornblende and epidote are the prevailing constituents, and horn- 
blende in either case occurs in broad blades. 

The Bay View greenstones are composed of hornblende and epi- 
dote, with a little chlorite, which constitute the mass of the rock. 
Scanty interstitial quartz and feldspar still remains. 

It can hardly be questioned that lime has been brought to the 
rock and thus assisted in the formation of these secondary constituents. 



138 



THE CRYSTALLINE ROCKS OF CECIL COUNTY 



It will be seen from the analysis which follows that in the fresh 
rock there is not sufficient lime for the formation in such excess of 
hornblende and epidote. 



CHEMICAL COMPOSITION. 



I. 

SiO„ 75.67 

A1 2 0„ 12.28 

Fe 2 3 85' 

FeO 2.59 1 

MgO 37 

CaO 2.65 

Na 2 3.63 

K 2 78 

H.,0 + 29 

H 2 - 12 

TiO., 29 

Zr0 2 none 

C0 2 trace 

P 2 6 05 

S0 3 

CI 

F 

S 11" 

Cr 2 3 

NiO 

MnO is 

BaO 07 

SrO trace (?) 

Li 2 none 

Total 99.93 



II. 

73.69 

12.89 

1.02 

2.58 

.50 

3.74 

2. 81 

1.48 

1.06 



RECALCULATION. 

Quartz 44.76 

Orthoclase 4.50 

Albite molecule . . . .30.57 ) 
Anortbite molecule. . 2.79 j 12 ' 

Biotite 8.04 

Garnet 5.78 

Titanite 76 

Magnetite 1.21 

Apatite 12 

Misc 48 

Total 99 01 



99.74 



I. — Analysis of acid dike-rock. 

II. — Port Deposit granite-gneiss (quartz-monzonites). 

Analysis made by W. F. ITillebrand of the United States Geological Survey. 



1 The FeO figure includes the iron of pyrrhotite. Both this and the Fe 2 O a figure 
are further in error by any reduction of the Fe 2 3 that may have resulted from the 
action of H 2 S set free from the pyrrhotite. An exact determination of these errors 
is impossible. 

Mainly as pyrrhotite. 



MARYLAND GEOLOGICAL SURVEY 139 

The analysis of this rock bears a marked resemblance to that of 
the quartz-monzonite, into which it intrudes. This analysis has been 
tabulated with it for the purpose of easy comparison. 

The difference lies in the greater acidity of the dike rock, the 
silica percentage is higher and the lime percentage is lower than in 
the monzonite. In both rocks the soda percentage is greater than 
the potassa. This difference is more marked in the secondary intru- 
sive. 

The chemical difference is just such as would be expected between 
a large intrusive body, representing an early stage in magmatic differ- 
entiation, and the material which fills fissures in this body and which 
represents a subsequent stage of differentiation. 

The feldspar was calculated as Ab i2 An x . The extinctions that 
were secured were high on 010 (15°-20°), and very low on 001 
(3°-4°). 

The lime that remained after the calculation of the anorthite mole- 
cule and apatite and titanite, was referred to the garnet. This con- 
stituent is distributed in microscopic crystals, somewhat sparsely 
throughout the slide, and can scarcely have developed at the expense 
of the feldspar. It is considered a primary constituent. It does not 
occur where the rock has been altered to a greenstone. 

The chemical composition, the mineral constitution, and the struc- 
ture of the rock is that of a rhyolite. Its alteration is so extended 
and has been of such a character as to obscure or obliterate the 
original structure, hence the rock must be classed with the meta- 
rhyolites. 

MICRO-GRANITIC DIKES. 

Within the meta-rhyolite are dikes of varying width of a fine- 
grained hornblende-granite containing quartz, albitic feldspar and 
hornblende with accessory magnetite. 

A determination of the alkali, lime and silica shows the rock to be 
of about the same acidity as the more basic quartz-monzonite of the 
granitoid belt, but richer in soda. 



140 THE CRYSTALLINE KOCKS OF CECIL COUNTY 

The percentages are as follows: 

SiO„ 69.17 

CaO 2.93 

Na.,0 5.70 

K 2 20 

Determined by W. F. Hillebrand of the U. S. Geological Survey. 

Albite is a predominating constituent. 

These dikes widen to the southwest and dwindle to the northeast. 

META-GABBRO. 

Some homblendic dike rocks, in the town and immediate vicinity 
of Port Deposit have been described on page 97. 

The few microscopic slides that were secured of these show 
epidote, hornblende, quartz and feldspar as the constituents. The 
first two predominate. The green hornblende bears the aspect of a 
secondary product from pyroxene. Epidote is a reactionary product 
of the ferromagnesian constituent and the feldspar. 

Quartz occurs in a granulated mosaic and in veins which may be 
secondary. The feldspar shows polysynthetic twinning. It is gran- 
ular in character and so crushed or altered as not to admit of indu- 
bitable determination of its species. The equal extinction angles 
are high and an extinction of 38° w r as obtained on the basal pinacoid. 
These results led to the conclusion that considerable basic feldspar 
was present. 

In the absence of a chemical analysis of these rocks, they are placed 
somewhat provisionally with the meta-gabbro. 

DIABASE. 

The location and the character of the outcrops of the diabase dikes 
have been given (pp. 100-101). Of the two dikes, one possesses a 
greater width and coarser grain than the other. Both are composed of 
material which, when fresh, is of a dark stone-grey color and a dense 
texture. When the rock is altered the color changes to green owing 
to the development of hornblende and epidote. The weathered sur- 



MARYLAND GEOLOGICAL SURVEY 141 

face is a reddish yellow. The rock readily weathers into cubical 
blocks possessing this oxidized crust, which penetrates to variable 
depths, and encloses a dark green or gray center. 

The two essential constituents of the diabase are present in the 
usual proportion and exhibit characteristic diabasic structure. 

There are two varieties of pyroxene, a violet colored augite and 
a colorless monoclinic pyroxene, which is both more idiomorphic and 
more altered than the augite. It resembles salite, but differs from 
this variety of pyroxene in the possession of a smaller optical angle. 
The narrowly lath-shaped feldspar is a basic labradorite (Ab 2 An 3 — 
Ab 3 An 2 ). Magnetite and apatite are accessory constituents. The 
constituents are remarkably fresh. The pyroxene shows some slight 
alteration to green hornblende, but the more conspicuous alteration 
product is a yellowish chlorite which exhibits the double refraction 
and other characters of delessite. This more often replaces the color- 
less pyroxene, but is also an alteration product of the augite and of 
the labradorite. Calcite is a very minor alteration product. 

The rock does not vary in any essential respect from the Triassic 
diabase of West Rock, New Haven, which has been described 1 in 
detail by Professor Pirsson. 



CHEMICAL COMPOSITION. 



Si0 2 .... 
Al 2 O a .. 
Fe 2 3 . . 

FeO 

MgO... . 

CaO 

Na 2 0.... 
K 2 . . . . 
Ignition 
Ti0 2 . . . 
P 2 5 .... 
MnO .... 



101.04 
I. — Diabase dike at Williamson's Point, Lancaster Co., Pa. 
II. — Diabase from York Co., Pa. 

Analysis made by Dr. F. A. Genth, Jr., Penn. 2nd Geol. Surv. Vols. CCC, p. 275, 
and C, p. 123. 

bulletin No. 150, U. S. Geol. Surv., pp. 2(54-273. 



I. 




II. 


50.79 




52.53 


14.19 




14.35 


3.84 




5.93 


7.44 




5.45 


7.88 




7.99 


9.75 




10.27 


1.89 




1.87 


.95 




.92 


1.95 




1.23 


.70 




.32 


.15 




.15 


.48 




trace 




s 


08 


100.01 


Cu 


trace 




Li 2 .. 


. . faintest trace 



142 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

Xo analysis was secured of the Cecil county diabase, which undoubt- 
edly is uniform in composition with that of the Pennsylvania diabase. 

Several analyses have been made of the Triassic diabase of 
Pennsylvania, and the two which have been selected represent mater- 
ial not far from the State line. 

They show the normal composition of a labradorite-augite rock. 

Summary. 

The crystallines of Cecil county embrace metamorphic rocks of 
aqueous origin and of igneous origin. The former class is represented 
by a mica-gneiss of a heterogeneous lithologic character with stratifi- 
cation planes dipping southeast. The thickness of the formation 
does not admit of determination. The structure is presumably one 
of gentle overturned folding, giving a dip varying from a low angle 
southeast to verticality. The relation of this formation in Penn- 
sylvania to known Paleozoics, and to presumably Paleozoic sedi- 
ments, appears to be that of conformable stratification. 

The possibility of a faulted structure is also recognized. The 
presence of a fault renders the formation pre-Paleozoic. In its 
absence it is presumably Paleozoic. 

Into this mica-gneiss have been intruded: 

1) igneous material of medium acidity (quartz-monzonite), which 
in turn includes intrusions of greater acidity (rhyolite) and of greater 
basicity (gabbro); 

2) basic igneous material (norite and quartz-norite) and 

3) ultra-basic material (pyroxenite and peridotite). 

All of these types show metamorphism. The quartz-monzonite is 
altered to a gneiss, the rhyolite to a meta-rhyolite, the gabbro, norite 
and quartz-norite to meta-gabbro and mota-quai tz-gabbro, the pyrox- 
enite and peridotite to amphibolite, serpentine and soapstone. In 
the acid and basic rocks metasomatism has been of the nature of 
epidotization, zoisitization and uralitization. In the ultra-basic rocks 
uralitization, serpentinitization and steatitization have been the pro- 
cesses of metasomatism. 

The age of these intrusives must remain problematical until the 
age of the mien-gneiss, into which they intrude, has been determined. 



MARYLAND GEOLOGICAL SURVEY 



143 



The youngest crystalline formations of Cecil county are sundry 
small diabase dikes of Triassic age. These resemble in every 
particular the diabase of the Triassic, which forms notable high- 
lands in the northeast, where it has been thoroughly investigated and 
described. 



GLOSSARY OF GEOLOGICAL TERMS. 

The rocks found at the surface of the earth have been formed in one 
of three ways. They are the product of consolidation from a heated 
molten state; they are the accumulation of fragments of disintegrated 
rock, which have been carried mechanically by running water and me- 
chanically deposited or have been carried in solution by running water 
and deposited by means of chemical precipitation or through the agency 
of organisms; or they are modified representatives of members of the 
first or second class which have been changed or metamorphosed by forces 
which have acted upon them. Rocks of the first class are called Igneous; 
those of the second, Sedimentary; and those of the third, Metamorphic. 

The Igneous rocks are subdivided according to their chemical composi- 
tion, more or less perfectly expressed by the minerals of which they are 
composed; and their texture, or manner in which the mineral constitu- 
ents are distributed in the rock. 

Since the species of the common light-colored mineral feldspar, or the 
closely related feldspathoids, varies with the chemical composition of the 
rock, it is customary to divide the Igneous rocks into the several divis- 
ions which, with the few additional subdivisions rendered necessary by 
the abundance of certain types, form the different families of igneous 
rocks. 

Each of these families defined by its chemical and mineralogical com- 
position is subdivided according to the differences in texture which de- 
pend upon the circumstances under which the rock consolidated and 
which often indicate the relative distance beneath the surface of the 
earth at which a given rock was formed. 

A combination of these various factors of chemical and mineralogical 
composition and texture applied to the rocks found in Maryland leads to 
the following: 

Classification of Igneous Rocks found in Maryland. 



Potash 
feldspar. 

Granular. Granite, 
texture. 

Fine grained 
granular or 
ophitic 
texture. 

Porphyritic, Rhyolite 
microgranular 
or glassy 
texture. 



Soda-lime feldspar. 
Monzonite. Diorite. 



Lime-soda 
feldspar. 

Gabbro. 
Norite. 

Diabase. 



Basalt. 



No feldspar. 

Pyroxenite and 
Peridotite. 



144 THE CRYSTALLINE KOCKS OF CECIL COUNTY 

Bach of these types carries one or more dark-colored minerals and 
sometimes other light-colored minerals and the minor subdivisions are 
based on which of these are present. Sometimes the name of the mineral 
is attached to the family name as, for example, hornblende granite; or at 
other times a new name is used, such as norite, which is applied to a 
member of the gabbro family in which the most important dark-colored 
mineral is hypersthene. 

The Sedimentary rocks are composed almost entirely of deposits formed 
under water by the accumulation of rock or mineral fragments, by or- 
ganic agency or bj' chemical action. The rocks differ widely in compo- 
sition and character and do not allow as strict a classification as do the 
igneous rocks. They may be divided first according to their composition 
into: — 

Arenaceous, or more or less coarse-grained sandy or pebbly deposits; 

Argillaceous, or fine-grained, clay-like or earthy deposits; 

Calcareous, or composed essentially of carbonate of lime, to which might 
be added a fourth; 

Pyroclastic deposits, composed primarily of volcanic dust and ashes. 

According to their coarseness and the shape of their constituents may 
be distinguished: 

Among the first: sands and sandstones, gravels, grits and conglom- 
erates. 

Among the second: clays, mudstones, shales and clay-slates. 

Among the third: marls, greensands and limestones. 

Among the fourth: volcanic dust, tuffs, breccias and conglomerates. 

Almost all of the sedimentary rocks show a stratified arrangement of 
their constituents which generally lie in approximately parallel planes. 

The Metamorphic rocks are formed from either sedimentary or igneous 
rocks when the latter are changed in composition and texture by the 
recrystallization that goes on when rocks are subjected to pressure or 
heat in the earth-movements which are constantly taking place. The 
metamorphic rocks are frequently rendered platy or schistose by the 
recrystallization under pressure, and they are accordingly often de- 
scribed as schists. Just as their origin is more complicated than that 
of 1he igneous or sedimentary rocks, so their classification is less thor- 
oughly worked out. If the character of the original rock is known to 
be some type of igneous rock it is customary to prefix the term meta to 
the name of the original rock. Thus, meta-gabbro is applied to meta- 
morphic rock which is known to have been originally a gabbro. 

Some of the more technical words used in the descriptions of the rocks 
may be defined as follows: 

Acidity. — A term used to indicate the amount of acid, usually silicic 
acid, compared with the amount of metals, such as iron and magnesium. 
Igneous rocks usually grow lighter in weight and color with increasing 
acidity. 

Actinolitr. — A fibrous green silicate of lime, magnesium and iron. Usu- 
ally the product of metamorphic changes in rocks. 



MARYLAND GEOLOGICAL SURVEY 145 

Allanitc. — A pitch-brown silicate of the rare earths, occasionally found 
in granite and other rocks, usually in minute specks. 

Allotriomorphic. — Applied to the constituents of igneous rocks whose forms 
are determined by the earlier formed constituents. Antinque of idiomor- 
phic. 

Amphioolite. — A grayish-green, fine-grained, metamorphic rock, com- 
posed essentially of hornblende and plagioclase feldspar, sometimes called 
hornblende-schist. It includes certain of the meta-gabbros. 

Amygdaloidal Structure. — A porous structure of certain igneous rocks in 
which the elliptical holes formed by the escaping gas have been filled 
with secondary minerals. 

Anthopliyllite. — A fibrous green silicate of magnesium and iron very 
similar to actinolite. 

Apatite. — A vitreous greenish or colorless phosphate of lime. In Mary- 
land rocks it is usually only in microscopic grains. 

Aphanitic. — A texture of igneous rocks in which the individual grains 
are visible only with the microscope. 

Apophysis.— One of the lateral projections of certain intrusive igneous 
rocks; often equivalent to dike. 

Basicity. — The relative amount of bases such as lime or iron, in igneous 
rocks. The opposite of acidity. 

Biotite. — A brown, green or black platy silicate of iron and magnesium. 
A member of the mica family and a prominent constituent in granites, 
gneisses and other micaceous rocks. Sometimes called black " isinglass." 

Brucite. — A pearly white to grayish-green hydrate of magnesium, fre- 
quently found in serpentine and marbles. 

Calcite. — Lime carbonate, usually colorless or white. It occurs in crys- 
tals or as limestone, marble and stalactites. 

Clmlcedony. — A waxy, transparent, close-grained quartz, often lining or 
filling cavities in serpentine. Sometimes found looking like hard glue. 

Chlorite. — A green tabular or scaly hydro-silicate of magnesium, alu- 
minum, and iron. Due to changes since the formation of the original rock. 

Clinochlore. — A variety of chlorite. 

Conglomerate.— A sedimentary rock composed of rounded and water-worn 
pebbles or fragments of pre-existing rock. (Puddingstone.) 

Creep.— Slow down-hill movement of surface-rock due to gravity. 

Deweylite. — An amorphous resinous white hydrous-magnesium silicate, 
related to serpentine. 

Diabase. — A compact heavy igneous rock, dark gray, dark green, or 
black, composed of plagioclase feldspar, pyroxene, iron oxide, and some- 
times olivine. Frequently called trap. 

Diastrophic. — Relating to the movement of the earth's crust, producing 
continents, mountains, folds and faults. 

Dike.— A mass of igneous rock filling a fissure in other rocks into which 
it has been intruded while in a liquid condition. 
10 



140 THE CRYSTALLINE BOCKS OF CECIL COUNTY 

Diorite. — A granular igneous rock of grayish-white or green color com- 
posed essentially of plagioclase feldspar, and hornblende or mica. It 
differs from monzonite in its lack of orthoclase feldspar and from gabbro 
in the acidity of its feldspar. 

Dip. — The angle of inclination of strata to the horizon, measured at the 
steepest point. 

Epidvte. — A yellowish-green granular or fibrous aluminum-silicate of 
lime. The epidote group includes zoisite, epidote, piedmontite, and allan- 
ite. 

Extrusive. — An igneous rock which has cooled at the surface from a 
molten state; a lava. 

Feldspars. — A group of light-colored silicates of aluminum and lime, 
soda, or potash. The species vary with the composition of the mass in 
igneous rocks and form the basis for a classification of these rocks. The 
species are: orthoclase microcline and sanidine, the potash feldspars; alhite. 
the soda feldspar; anorthite, a lime feldspar; olif/ochise, labradorite and 
bytownite intermediates between albite and anorthite, i. e., soda-lime and 
lime-soda feldspars. The feldspars of the albite-anorthite series are col- 
lectively called plagioclase. 

Gabbro. — A granular, igneous rock of dark color, composed essentially 
of lime-soda feldspar and a pyroxene. Sometimes sold as black granite — 
popularly called " nigger head." 

Garnet. — A transparent, generally reddish-brown silicate of iron, lime 
and alumina frequently found in small crystals. 

Gneiss. — A metamorphic rock, composed of feldspar, quartz, and mica, 
arranged in banded layers. When appended to the name of an igneous 
rock it implies that the latter has been metamorphosed with the rear- 
rangements of the constituents into parallel lines. E.g., granite-gneiss. 

Granite. — A granular aggregate of feldspar and quartz with accessory 
mica or hornblende which has resulted from the crystallization of a 
molten mass under conditions of high temperature and high pressure. 

Granular. — Composed of irregularly-shaped grains of approximately equal 
size. 

Greenstone. — A common term applied loosely to various kinds of green- 
ish rocks generally of igneous origin. 

Hematite. — Red oxide of iron. 

Hornblende. — A greenish-black, often fibrous, iron magnesium silicate 
formed by crystallization from a molten state, as in the hornblende- gran- 
ites; or by crystallization from pyroxene through metamorphism, as in 
meta-gabbro. 

Hydro-magneHte. — A basic magnesium carbonate occurring as a tufted 
or chalky crust on serpentines. 

Hi/persthene. — A pearly, dark-colored, brittle iron magnesium pyroxene, 
frequently found in gabbro and allied rocks. 

TdfiOmorpMc. Applied to constituents of igneous rocks which have formed 
under conditions permitting the development of their characteristic crystal 
forms. 



MARYLAND GEOLOGICAL SURVEY 147 

Igneous. — Formed from a molten state. This does not imply fire but in- 
tense heat. 

Inlier. — A former outlier or uneroded portion of an older rock which 
having- formed an island or an elevation owing to some later deposit has 
thus become embedded in a younger rock. E. g., Grays Hill near Elkton. 

Intrusive. — An igneous rock which has been injected into cavities in pre- 
existent rocks and there cooled. 

Limonite. — A brown hydroxide of iron. Iron rust. A brown hematite. 

Magncsite. A white, often chalky mineral occurring in veins or coat- 
ings on serpentine; often adheres to the tongue when moistened. A car- 
bonate of magnesia. 

Magnetite. — The magnetic oxide of iron, usualty in minute black dia- 
monds. 

Met a. — A prefix used to indicate that the rock has been formed by a 
metamorphism of the rock to which the prefix is attached. 

Metamorphism. — Changes that go on in rocks due to re-crystallization 
with or without alteration in the chemical composition of the mass. 
These changes are due to modifications of the rock's environment which 
render the original minerals unstable. 

Norite. — A dark-colored granular igneous rock composed essentially of 
a basic lime-soda feldspar and an enstatite or a hypersthene. 

Olivine. — Pale yellowish-green vitreous silicate of iron and magnesium 
formed in igneous rocks of low silica content. 

Ophitic. — The texture of rocks produced by the intergrowth of lath-shaped 
feldspars and augite. 

Orogenie. — Due to the forces which have formed or are forming moun- 
tains. 

Orthoclase. — A variety of feldspar, abundant in granites. 

Outliers. — A portion of rock-mass that remains in position while the 
originally contiguous portions have been removed by erosion. For ex- 
ample, the gravel cappings near Pleasant Hill. 

Pegmatite. — A very coarse-grained granitic rock composed of orthoclase, 
quartz and mica, occurring as veins or dikes in other rocks. 

Peridotite. — A granular, igneous rock composed of olivine and other 
iron and magnesian minerals. Usually changed to serpentine. 

Picrolite. — A columnar or fibrous variety of serpentine. 

Plagioclase. — The soda-lime and lime-soda feldspars including albite, oligo- 
clase, labradorite, bytownite and anorthite. 

Porphgritic. — A texture in which larger crystals are imbedded in a back- 
ground of finer grain or glass. 

Pgroxenite. — A granular, igneous rock, composed essentially of iron and 
magnesian minerals and differing from peridotites by a lack of olivine, 
and from gabbro, by a lack of feldspar. 

Quartzite. — A very compact, granular quartz-rock, formed by the harden- 
ing of a sandstone through the secondary deposition of silicious cement. 



148 THE CRYSTALLINE ROCKS OF CECIL COUNTY 

It utile. — A reddish-brown transparent to opaque oxide of titanium, 
occasionally found as fine plates or prisms in serpentines and other rocks. 

saii.ssiirite. — 

Schist. — A rock that has a parallel or foliated structure developed in it 
by shearing through recrystallization of the constituents in parallel 
layers. 

Schistosity. — The secondary foliation or imperfect cleavage produced in 
schists during metamorphism. 

Sedimentary. — Formed originally of sediments deposited in water or air. 
The material is usually sand or clay derived from the debris brought 
down by rivers. 

Serpentine. — A massive platy or fibrous l^drous magnesium silicate usu- 
ally green in color. Also a rock composed principally of serpentine 
derived from the metamorphism of basic igneous rocks, such as peridotite. 

Soapstone. — A greasy, grayish-green metamorphic rock composed prin- 
cipally of the hydrous magnesium silicate talc or steatite. 

Staurolite. — A reddish-brown to brownish-black silicate of iron and 
aluminum often crystallizing in small crosses. 

Strike. — The direction of the intersection of an inclined bed of rock with 
the horizontal surface compared with a north and south line. This may 
be found by taking the direction at right angles to the greatest inclina- 
tion or dip. 

Talc. — A greasy, greenish- white, hydrous magnesium silicate. In the 
form of a rock often called soapstone. 

Tourmaline. — Usually a black, lustrous, complex silicate of iron, boron 
and aluminum, frequently recognized by its triangular cross-section. 

Tremolite. — A light-colored often fibrous lime-magnesium silicate. 

Trichoism. — The property of a mineral by which it transmits different 
colors in different directions. All of the colors are produced by the 
varying proportions of three axial colors polarized at right angles to 
each other. 

Viilliamsite. — A clear, more or less translucent variety of serpentine. 

Zaratite. — An emerald-green hydrous nickel carbonate found incrusting 
serpentine. 

Zircon. — A zirconium silicate often found in minute crystals in gran- 
ites and other rocks. 

Zois'xte. — A vitreous greenish-white magnesium silicate of aluminum 
frequently formed from the feldspar of basic rocks during metamorphism. 
A variety of epidote. 

E. B. M. 



THE GEOLOGY OF THE COASTAL PLAIN 
FORMATIONS 

BY 

GEORGE BURBANK SHATTUCK 



Introductory. 

Special attention is given in the following chapters to the stratig- 
raphy, structure and areal distribution of the various unconsolidated 
deposits found within the borders of Cecil county. These deposits 
are confined to the Coastal Plain except on its western border where 
they lap up on to the eastern edge of the crystalline rocks as they 
pass beneath the surface. The deposits of the Coastal Plain are 
very much younger than the rocks composing the Piedmont Plateau 
and the unconformity which separates them represents a great inter- 
val of time. . The geologic history of the Coastal Plain is a most com- 
plex and interesting one and covers a period extending from the 
Lower Cretaceous, or possibly Upper Jurassic, down to the present. 
The sequence of deposits, however, is not a continuous one but is 
interrupted frequently by unconformities when the region stood above 
ocean-level and was subjected to the destructive processes of erosion. 

The various formations of the Coastal Plain in Cecil county in their 
regular sequence of superposition are as follows: 

A S e - Formation. Group 

Pleistocene Talbot \ 

Wicomico [-Columbia. 

Sunderland \ 

Neocene Lafayette 

Eocene Aquia Pamunkey. 

Upper Cretaceous Monmouth 

Matawan 

Lower Cretaceous Raritan ) 

. „ Patapsco J. Potomac. 

Jurassic ? Patuxent 



150 Till-: COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

The oldest rocks of the Coastal Plain in Cecil county belong to the 
Potomac group and represenl the Lower Cretaceous or the Lower 
Cretaceous and Upper Jurassic They arc separable into three well- 
defined formations, which are known, beginning with the oldest, 
as the Patuxent, Patapsco and the Raritan. These deposits consist 
of clays, sands and gravels, and bear great numbers of fossil plant-. 
They were laid down in an estuary and are separated by a great 
unconformity from the rocks of the Piedmont Plateau on which 
they rest. The Upper Cretaceous rocks follow next in the series 
and consist of the Matawan and Monmouth formations. These beds 
are composed of (days, sands and greensands, yield a few animal 
remains and point to marine conditions of deposition. They lie un- 
conformably on the Potomac beds. The Aquia formation, the only 
representative of the Eocene, is the next member of the Coastal Plain 
series. It lies unconformably on the Upper Cretaceous beds and like 
them is composed of sand and greensand and points to the existence 
of an ocean over the region which it now occupies. Above the 
Eocene deposits and lying- unconformably on them is the Lafayette 
formation, which has been questionably referred to the Pliocene divi- 
sion of the Neocene. It consists of clays, sands and gravels. It was 
deposited in shallow water near shore but since its elevation above 
ocean-level has been so vigorously attacked by erosion that only a 
few outliers now remain along the western edge of the Coastal Plain 
and the eastern border of the Piedmont Plateau. The deposits now- 
occupying the greatest surface area of the comity belong to the Pleis- 
tocene. They are known collectively as the Columbia Group and are 
separated into the Sunderland, Wicomico and Talbot formations. 
They record many of the events which took place along the shore of 
the Pleistocene ocean when glaciers covered the surface of North 
America only a little way toward the north. They lie unconform- 
ably upon all formations which precede them and record an oscillating 
shore-line which constantly changed its position. 

In prosecuting the geological work nf Cecil county, the author has 
been assisted in the field by Messrs. F. B. Wright and 13. L. Miller. 
^Tr. A. Bibbins has also furnished numerous observations. 



maryland geological survey 151 

The Potomac Group. 1 

The western boundary of the Potomac group of Cecil county is 
a sinuous and interrupted line extending from the vicinity of Wood- 
lawn through Theodore, Bay View, Laurel Hill and Cherry Hill to 
Barksdale. Along this line the formation often consists of isolated 
outliers resting on ancient crystalline rocks. The eastern boundary 
of the Potomac area is much more regular and extends from the 
mouth of the Sassafras river to the western end of the Chesapeake 
and Delaware Canal. The Potomac beds, which are composed of 
clay, sand and gravel, are characterized by extreme diversity in com- 
position, texture and color, and by sudden and oft-repeated changes 
in the same, both horizontally and vertically. They are, on the 
whole, rich in iron oxide, and by it the sand and gravel beds are 
often locally indurated to sandstone and conglomerate. 

The fossils consist almost exclusively of plant remains, among 
which may be mentioned leaf impressions of ferns, cycads, conifers, 
monocotyledons and dicotyledons and wood altered to lignite or re- 
placed by various minerals. Semitransparent pellets of amber are 
occasionally found. 

The thickness of the beds has been estimated as about 600 feet at 
the mouth of the Sassafras and 420 feet near Chesapeake City. The 
strike runs from northeast to southwest, and the dip varies between 
30 and 60 feet per mile to the southeast. 

Only three of the four formations of the Potomac group are posi- 
tively recognized in Cecil county; these are the Patuxent, Patapsco 
and Earitan. The Arundel formation, which is so well developed 
farther south, if present here, is only slightly represented. 

THE PATUXENT FORMATION. 

The Patuxent formation is the basal member of the Potomac 
group, so called from its typical locality along the Patuxent river 
in Southern Maryland. It was formerly thought to be Lower Cre- 
taceous in age, but of late years it has been provisionally referred 

1 The discussion of the Potomac group is based on the field notes and manuscript 
of Mr. A. Bibbins, who placed them at the disposal of the writer. 



152 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

to the Jurassic. The Patuxent formation is developed in a broad 
belt extending across the county from the Delaware line to the 
Susquehanna river with an average width of about 5 miles. Its 
southern margin, where it passes beneath the overlying formations, 
is approximately coincident with the north shore of Northeast River 
as far as the town of Northeast, and from here to Iron Hill with the 
line of the Philadelphia, Wilmington and Baltimore Railroad. The 
northern border of the belt lies roughly parallel to the southern 
and passes through Barksdale, Cherry Hill, Egg Hill, Bay View, 
Theodore and Woodlawn. Throughout this belt the Patuxent for- 
mation is by no means continuously developed, but has suffered so 
from stream erosion that it is present in irregular masses and isolated 
outliers only. The formation has not only been removed from a 
great territory to the north over which it formerly extended, but has 
also been swept out of most of the stream channels which cross it. It 
is thus restricted to the divides and is found on them with circuitous 
and irregular outlines. The area possessing the greatest width is 
found on the western end of the belt, extending from a mile northwest 
of Woodlawn to the mouth of Furnace Creek with a width of 7 
miles. The formation is laid down unconformably on the under- 
lying crystalline rocks and unconformably beneath the deposits of 
later age. It is overlain throughout a portion of this belt with out- 
lying remnants of the Patapsco formation, the next younger member 
of the Potomac group, and also by sands and gravels of the Lafayette 
formation and the Columbia group. 

The materials making up the Patuxent formation are extremely 
varied. They consist of variegated clay^, sand, gravel, ironstone and 
conglomerate, both cross-bedded and horizontally stratified. These 
materials are not regularly distributed throughout the formation in 
well-defined and continuous beds, but alternate and change rapidly 
the one into the other both horizontally and vertically. As a whole 
the formation is predominantly sandy and bears an abundance of 
water. The great development of drab clay, which is described in 
the accompanying section, is a rather unusual occurrence of that 
sort of material in this formation. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XII. 




FIG. 1.— PATAPSCO AND RARITAN FORMATIONS, " LOWER WHITE BANKS." 



■ i maw-' * i- I'm* '■ • ' - ■ \ ■ H 




1pm 



Sft- 



Fig. 2.— NEARER VIEW OF RARITAN FORMATION, MAULDEN MOUNTAIN. 
GEOLOGICAL SECTIONS IN CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 153 

The strike of the formation extends across the county from north- 
east to southwest, and the normal dip is 60 feet per mile to the south- 
east. An exception to this dip is found in the southwestern part 
of the county, where the formation descends from an elevation of 
440 feet near Woodlawn to tide in a distance of 6 miles, making 
a dip of 74 feet per mile. This exceptionally high dip may possibly 
be accounted for by movement along the " Tall line." The thick- 
ness of the formation shows a maximum at Elkton of 142 feet, which 
was obtained by a well-boring at the City Pumping Station at that 
place. 

The unusual thickness is believed to be caused by the materials 
occupying a deep trough in the subjacent crystalline rocks. The 
following section is the one obtained during the sinking of the well 
at the Pumping Station. 

Section at Pumping Station Well, Elkton. 
Formations. Feet. 

Talbot. Sandy Loam 4 

Patuxent. White plastic clay 10 

Coarse and fine sand, bearing lignite 32 

Coarse water-bearing gravel, with abundant transparent quartz 

pebbles and some white clay 3 

Fine white quartz sand 7 

Tough drab lignitic clay 85 

Water-bearing sand 1 

The estimated thickness of the formation in the vicinity of Poplar 
Point is 60 feet. 

The fossils of the Patuxent formation in this county include ferns, 
cycads, and conifers. ISTo dicotyledons have, up to the present 
time, been discovered in this formation. These plant remains have 
largely been changed to lignite, and are found imbedded in the 
stratified black clays in the Broad Creek depression. 

THE PATAPSCO FORMATION. 

The Patapsco formation is so called because of its typical develop- 
ment along the Patapsco river near Baltimore. Its age, judging 
from the plant remains, which have been found imbedded in its 



1 5 1 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

clays is Lower Cretaceous. The formation rests unconformably on 
the underlying Patuxent formation, and is overlain unconformable 
not only by the Raritan, which is the next succeeding formation of 
the Potomac group, but also by the sands and gravels of the Lafayette 
formation and the formations of the Columbia group. The Patapsco 
formation occupies a belt extending across Cecil county, from the 
Delaware line to the Susquehanna river and the head of the Chesa- 
peake Bay, included roughly between the tracks of the Baltimore 
and Ohio Railroad on the north and the north shore of Elk River on 
the south. Throughout the northern portion of this belt the for- 
mation is exposed on the hillsides, and throughout the southern portion 
it is found at a lower level in the sides and bottoms of deep ravines. 
Throughout the northern half of the belt it overlies the Patuxent 
formation; throughout the southern half it is in turn overlain by the 
Raritan. Exceptions to this general rule are found, however, in 
some outlying areas, such as Egg Hill and localities near Foys Hill 
and Blythedale, where isolated portions of the Patapsco not only 
rest on the Patuxent, but are also largely covered over with Paritan. 

The materials of the Patapsco are fully as varied and irregularly 
developed as those of the Patuxent. They consist of variegated 
clays and stratified and cross-bedded sandstones, gravel and con- 
glomerate, but the formation as a whole is argillaceous and carries 
a large proportion of the clays of this county. Its sands, like those 
of the Patuxent formation, are water-bearing. The strike of the 
formation is from northeast to southwest, and the beds dip to the 
southeast at the rate of about 40 feet per mile. The thickness of the 
formation has been estimated at Turkey Point to be about 360 feet 
and at Chesapeake City as 200 feet. 

The Baltimore and Ohio Railroad cut at Toys Hill exposes the 
following section: 

Formation. Feet. 

Patapsco. Hurt' sands, water-bearing at base 35 

Dense, variegated clays 10—30 

Another good section is found in the deep cut of the Philadelphia, 
Wilmington and Baltimore Railroad, one and one-eighth miles east 
of Principio Creek. 



MARYLAND GEOLOGICAL SURVEY 155 

Section one and one-eighth miles east of Principio Creek. 
Formations. 

Feet. 
Recent. Loani-bearino- gravel. - 

o 

Rantau. Fine white sand 

Brown loamy sand, bearing gravel and arkose toward base 12 

Patapsco. White clay, somewhat iron-stained and variegated ; at times grad- 
ing over into micaceous sands; changing to gravel, arkose 
conglomerate toward base ' jo-20 

Dense, variegated clays. 1() 

The fossils of the Patapsco formation in this county consist of 
ferns, cycads, conifers and a few dicotyledons. Species of the latter 
found in the uppermost beds possess well-marked modern affinities. 

THE RARITAN FORMATION. 

The Raritan formation is so called because of its typical develop- 
ment about Raritan Bay in New Jersey. Its age, judging from the 
plant remains which are found imbedded in its clays, is Lower Cre- 
taceous. It lies unconformable on the Patapsco, and is overlain 
unconformable by the beds of Upper Cretaceous age. The Raritan 
formation occupies the greater part of the high land of Elk Neck, 
extending from the Baltimore and Ohio Railroad on the north to 
Turkey Point on the south. It is underlain throughout this district 
by the Patapsco formation which is found exposed in the lowland 
bordering either side of the peninsula, as well as in the beds of the 
streams which cut through the Raritan formation. On the east side 
of Elk River, the Raritan formation is also found occupying the low 
ground along the river and occupying the beds of the streams for a 
distance of _3 or 4 miles. East of the Elk River it rapidly disappears 
below the overlying beds of younger age. Besides these continuous 
areas of Raritan, there are also a few outliers of the same formations 
which are found at Singerly near Childs, at Egg Hill, at Foys Hill 
and at the hill to the northwest of it. 

The materials of the Raritan formation are similar in kind and in 
distribution to those making up the Patuxent and Patapsco forma- 
tions. They consist of variegated clays and horizontally stratified 
and cross-bedded sands, gravels, sandstone and conglomerate. They 
are not regularly developed over great areas, but change abruptly 



15G THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

into each other both horizontally and vertically. The Raritan for- 
mation in Cecil county is, however, on the whole, a sandy terrane, 
in this respect resembling the Patuxent formation. Its upper and 
lower portions are important water-bearing horizons. 

The strike of the Raritan formation is from northeast to southwest, 
and the dip is about 30 feet per mile to the southeast. The thick- 
ness of the formation has been estimated as 180 feet at the mouth 
of the Sassafras river, and is 60 feet at the west end of the Chesa- 
peake and Delaware Canal. Two of the most instructive sections of 
the Potomac group are found in Cecil county; one is in the famous 
cliffs at lower White Banks, and the other is at Maulden Mountain. 

Section at Lower White Banks. 

Formations. Feet. 

Lafayette. Loam and gravel 0-6 

Raritan. White sandy clay (" fullers earth ") 25 

Buff and brown cross-bedded sand, brightly iron tinted in its mid- 
dle and lower portions, containing pebbles of white clay, indu- 
rated below 20 

Light drab clay 2 

Fine, drab plastic clay, laminated above, obscurely stratified below, 

rich in leaf impressions 2 

Light drab and bun", laminated clays, with fine white sand 2 

Light colored sand, locally indurated 10-15 

Patapsco. Variegated and drab clays mostly obscured by talus 20 

Section at Maulden Mountain. 
Formations. Feet. 

Lafayette. Loam and gravel 6 

Matawan Massive micaceous glauconitic sand, more or less indurated near 

top 30 

Loose, light colored sand, with less glauconite, oxidized at the sur- 
face, containing brown tlecks 6 

Sharp white and yellow sand, indurated at base 3 

Yellow, ni] and ash-colored clay 2 

Loose, light colored sand, with glauconite containing brown flecks, 

micaceous and more argillaceous toward the base 15 

Lens of loose carbonaceous sandy loam bearing pyrite, grave] at 

base, 

Raritan. Lens of stratified, iron-stained, at times pebbly, clay, occasionally 

lignitic, indurated at base 3-10 

Light bull' and brown cross-bedded sand 25 

Ledge of ferruginous sandstone 2-'.) 

Light buff and brown cross-bedded sand, brightly iron tinted in 
t be middle and lower portions and containing white clay pebbles 

and pelbts. indurated at base 15 

Patapsco. Massive variegated and drab Lignitic plastic clays, the latter at 

times containing iron carbonate, mostly obscured by talus.... 20 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XIII. 




FlG. 1.— RARITAN FORMATION OVERLAIN BY MATAWAN, GROVE POINT. 




Fig. 2.— RARITAN FORMATION OVERLAIN BY PLEISTOCENE, NORTHEAST RIVER. 
GEOLOGICAL SECTIONS IN CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 157 

The fossils of the Raritan formation in this county consist largely 
of plant remains, and among these is a large proportion of dicotyle- 
dons showing a very noticeable advance in grade of organization over 
those of the Patapsco formation. Leaf bed occurs at upper White 
Banks, at lower White Banks, at Turkey Point, Grove Point, and 
other localities near the west end of the Chesapeake and Delaware 
Canal. At Grove Point small pellets and grains of amber have been 
found preserved with other remains of vegetable life. The drab clays 
of this formation are commonly lignite-bearing and the logs, especially 
toward the summit of the terrane, are occasionally teredo-bored. 

The Upper Cretaceous Formations. 

Deposits of Upper Cretaceous age are developed only in the south- 
eastern portion of Cecil county. In the Eastern Shore portion of the 
county, south of Back Creek and the Chesapeake and Delaware Canal, 
the various formations occur in the banks and beds of creeks and 
rivers wherever erosion has been sufficient to remove the surface 
cover of Pleistocene sand and loam. Exposures of the deposits are 
met with in the banks of both the Great and Little Bohemia creeks 
and their tributaries and in Cabin John and Pierce creeks; but the 
greatest development and most continuous outcrops are found at 
Grove Point and up the Sassafras river as far as Fredericktown. 

The distribution of the Upper Cretaceous formations is quite con- 
tinuous. Only one outlier is known, and this is located in the high 
slopes of Maulden Mountain on Elk ]STeck. 

The materials which compose the beds of the Upper Cretaceous 
formations consist of clays, sands, greensands and marls, and are quite 
uniform in their constitution over wide areas. Locally iron oxide 
has entered so largely as to have transformed them into sandstone. 
There is then the greatest contrast between them and the beds of 
the Potomac. The latter are noted for their brilliant and gaily- 
colored clays, which may be distinctly seen for many miles; the 
former, however, are usually of the most sombre tints of drab, 
greenish-black and black, with these monotonous colors only occa- 
sionally relieved by the dull red tint of iron oxide. 



158 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

In Cecil county the beds of Upper Cretaceous age are not rich in 
fossils. Remains of marine mollusca have been discovered, but the 
forms have not been as yet thoroughly collected and studied. They 
are frequently in an advanced state of dissolution. 

THE MATAWAN FOBMATION. 

The Matawan formation is the basal division of the Upper Creta- 
ceous deposits of Maryland. It is so called from its great develop- 
ment along the Matawan river of New Jersey. It is the oldest repre- 
sentative of the Upper Cretaceous in Cecil county and is developed 
along the Coastal Plain from Atlantic Highlands to the Potomac 
river. It lies unconformably on the Raritan formation, the upper- 
most member of the Potomac group, but is overlain conformably by 
the Monmouth formation, the next younger member of the Upper 
( iretaceous. In Cecil county it is found within a very narrow strip 
of country, scarcely exceeding three miles in width, which extends 
from the north bank of Bohemia River to Grove Point. Outside 
< f this district it is found in only one other locality, near the top 
of Maulden Mountain. Although the Matawan undoubtedly forms 
the substratum throughout the former area, still it is so largely 
covered up by deposits of later age that good exposures are less com- 
mon than might be expected. In only two localities does this form- 
ation come prominently into view, namely, al Maulden Mountain and 
Grove Point. At the former locality, on the western side of the 
mountain, there is a steep sea-cliff, extending from the shore of Ches- 
apeake Bay to a height of 170 feet. The lower 90 feet of this ex- 
posure is composed of sands and clays belonging to the Potomac group. 
Resting immediately and unconformably upon these beds are 60 
feet of Matawan having a dusty green color. These are overlain in 
turn with a bed of gravel and loam belonging to the Lafayette form- 
ation. The Matawan beds of Maulden Mountain are slightly mica- 
ceous and glauconitic. This latter characteristic is particularly evi- 
dent near the center of the bed. Its upper portions show little or 
no lamination, but at its base thin iron crusts appear which lie imme- 
diately above a narrow band of dark to light gray clay, which has 
been referred to the Raritan formation. 



MARYLAND GEOLOGICAL SURVEY 159 

At Grove Point the waves of Chesapeake Bay have cut a clean 
and almost perpendicular sea-cliff, varying in height from 20 to 50 
or (30 feet. Toward the northern end of this escarpment the 
Earitan appears at the base, but throughout the middle and southern 
portions of this sea-cliff the base of the precipice is composed of the 
Matawan formation. At this place it is made up of a dense and 
slightly micaceous, bluish green clay, which rises in a perpendicular 
bank to a height varying from 5 to 20 feet above tide. It lies here, 
as well as on Maulden Mountain, unconformably on the Earitan. 
This relation of the two deposits is clearly shown at the northern 
end of the cliff (Plate XIII, Fig. 1). Toward the southern end the 
contact disappears below tide, and the Matawan gradually passes 
down deeper and deeper beneath the beach. In this locality the 
Matawan contains considerable lignite and pyrite and is strongly 
impregnated with sulphur, as is indicated by the strong odor arising 
from the exposed surfaces. Above the Matawan there is an uncon- 
formable mass of loam, sand and gravel of varying thickness belong- 
ing to the Columbia group. Other exposures of Matawan in Cecil 
county are of minor importance and of inferior character. 

The structure of the Matawan formation is as simple as that of 
the underlying Potomac beds. It crosses the county from northeast 
to southwest, and dips beneath the overlying formations at the rate 
of about 20 feet to the mile. 

Up to the present time the Matawan has yielded in this county 
no other fossils than lignite. 

THE MONMOUTH FORMATION. 

The Monmouth formation, named from its typical locality in Mon- 
mouth county, Xew Jersey, has been divided into two members, 
the JSTavesink marls at the base and the Eed Bank sands above. 
The Navesink is typically exposed in the Xavesink Highlands, New 
Jersey, and the Eed Bank sands in the vicinity of Eed Bank in the 
same state. These two localities suggest the names which have 
been applied to these members of the Monmouth formation. The 
Monmouth is Upper Cretaceous in age, lies conformably on the 



160 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

Matawan formation, and is overlain conformably by the Aquia. 
It is developed in Cecil county in a continuous belt some six or seven 
miles in width, extending from the vicinity of Chesapeake City to 
the Sassafras river. Throughout most of this region the Monmouth 
formation is largely covered up by sand and gravel of the Columbia 
beds. 

The Xavesink Marls. — The outcrops of the Navesink marls are 
restricted to a series of more or less detached exposures occurring 
along the Sassafras river and Bohemia Creek. On the Sassafras 
river these exposures extend from Grove Point to a little beyond Cas- 
sidy Wharf. Along Bohemia Creek the outcrops occur in the lower 
valleys of the small tributaries, especially along Scotchman Creek 
and the little stream just east of it. Other exposures of secondary 
importance occur in Pierce and Pond creeks. Of the exposures in 
the Sassafras basin, three are of particular interest. The first one 
is found about one mile and a half up the river from Grove Point. 
Here are exposed about 20 feet of fine, slightly micaceous sand, 
intermixed with other sand stained brown by iron so as to give to 
the whole a mottled appearance. Within the iron-stained parts are 
small pockets of gray-green glauconitic sand. The whole is so imper- 
fectly cemented together that it quickly weathers down to a loose 
deposit. Under the microscope the grains of sand are rather angu- 
lar. Those from the more ferruginous parts are completely coated 
with iron, while those from the lighter colored pockets are entirely 
free from it. Glauconite is found in these lighter patches, giving 
them a greenish tint. The outcrop can be traced in the bank around 
the swamps beyond Cassidy Wharf, with only now and then a 
break where the Columbia gravels completely cover it. The best 
exposures occur near Ordinary Point. The thickness of the ISTave- 
.sink here increases to a maximum of 45 feet, and then decreases 
rapidly and disappears under the lower terrace which forms the 
point. This section shows a little valley in the Xavesink, some 25 
feet deep, that has been filled with Columbia gravel. 

On the east bank of the creek above Ordinary Point the ISTavesink 
formation appears again and can be traced, although the exposures 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XIV. 




Fig. 1. -cliff showing matawan-monmouth contact, sassafras river. 




Fig. 2.— bluff showing eocene, at Georgetown. 



GEOLOGICAL SECTIONS IN CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 161 

are poor, around the banks of the swamp to the next point where the 
Columbia gravels again lap down to the water's edge. 

At Cassidy Wharf there is another good exposure of 20 feet, which 
shows the same characteristics as the one last described. The most 
easterly trace of the Navesink formation on the Sassafras river is 
along the bank of the little stream just above this wharf; beyond 
this it disappears below the Ked Bank sands. 

The exposures of the Bohemia Creek basin are as a whole very 
much inferior to those of the Sassafras river basin. Along Scotch- 
man Creek the ISTavesink formation appears in the bottom of the 
valley. In the west bank the Columbia gravels rest directly on it, 
while at the mill, three miles from the mouth of the creek, the Ked 
Bank sand comes in above. Here in the road-cut are exposed 
four feet of gray greenish to fine white micaceous Navesink sand, 
overlain by 12 feet of case-hardened Red Bank sand. The ISTavesink 
is composed mostly of quartz grains and mica flakes, with now and 
then a little iron coating the particles. 

On the north side of Bohemia Creek there is a small poorly exposed 
outcrop found in the first valley east of the bridge, and also another 
on the stream to the west of it. In these two localities the formation 
appears very similar to that last described. On Mr. Harriat's farm, 
just east of the bridge, some fragments of fossils were found and a 
few were well enough preserved for identification. In this neigh- 
borhood there are a number of deserted marl pits which have not 
been worked for a number of years. 

Two miles south of Pivot Bridge, on a branch of Back Creek, 
there is a section 55 feet high, showing at its base 20 feet of brown- 
ish-gray, micaceous sand bearing glauconite. This deposit is Nave- 
sink and is overlain by coarse reddish-brown, slightly case-hardened 
Red Bank sand. 

The ISTavesink marls of Cecil county have furnished very few 
fossils. However, some have been found on the banks of the lower 
Bohemia Creek, especially on Mr. Harriat's farm. Here were dis- 
covered Exogyra costata, Say.; Grypliaea vesicularia, Lamarck; 

Idonearca vulgaris, Morton; and Cardium perelongatum, Whitney, 
li 



162 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

The Red Bank Sands. — This member generally is a red, case-har- 
dened, rather coarse sand deposit, with here and there a pocket con- 
taining glauconitic sand. Locally there are lenses and quite extended 
beds of this glauconitic material. 

Outcrops of Red Bank sands are found quite continuously along 
the Sassafras river from the head of Back Creek around Knight 
Island, then up the river and its tributaries to one-quarter of a mile 
east of Fredericktown. More extensive exposures are found along 
the headwaters and eastern bank of Scotchman Creek; Little and 
Great Bohemia creeks, and their tributaries. The largest is at Bo- 
hemia Mills near the Delaware line, where a 40-foot section is well 
shown. 

Although the Red Bank sands are developed along the Sassafras 
river near Cassidy Wharf and Fredericktown, still typical exposures 
are rare. Along the banks of Back Creek and extending up the 
valley nearly to Earlville, Red Bank sands appeal 1 poorly exposed as 
a brown sand. Here it is somewhat case-hardened but not so firmly 
bound together as further east on the Sassafras river. The lower 
part of the valley west of Fredericktown shows a continuous outcrop 
of Red Bank for about 20 feet above the river. The formation is 
here coarse, brown to reddish-brown and much case-hardened, with a 
fossiliferous bed appearing here and there near the top. However, 
this furnishes few determinable fossil forms, as in most cases only the 
casts remain, and these in a coarse, iron-cemented sand which pre- 
serves almost no detail. One-half mile east of Fredericktown the 
formation disappears. . 

On the east bank of Scotchman Creek and along the headwaters 
of the creek east of Earlville, sections showing Red Bank sands are 
quite numerous. Just south of Bohemia Bridge the road-cut shows a 
fair exposure of reddish-brown sand, but little case-hardened, and 
bearing no glauconite. The outcrop further up the river is obscured 
by woods, but the first small tributary to Scotchman Creek crossed 
by the road going south from Bohemia Bridge shows a 30-foot sec- 
tion of this same coarse, reddish-brown sand. The first road to the 
west crosses a little stream where the Columbia a ravels contain re- 



MARYLAND GEOLOGICAL SURVEY 103 

worked Red Bank, and a short distance down the valley the forma- 
tion itself appears, although poorly exposed. Across the stream from 
the mill on Scotchman Creek is a very good exposure of Red Bank 
showing its contact with the Navesink below. Here the formation 
is a coarse, reddish-brown, case-hardened sand with little lenses and 
pockets of gray-green glauconitic sand, which are usually surrounded 
by a more or less developed layer of concretionary ironstone. Above 
the dam the continuance of this deposit is slightly indicated in places, 
and where the north and south road crosses a small tributary there 
is an exposure of 15 feet. 

On the east bank of the first stream east of Scotchman Creek at 
the road crossing there is a fine exposure of 25 feet of Red Bank. 
It is a loose, brown sand unaffected by case-hardening. By far the 
best exposure of the Red Bank sands is found at Bohemia Mills. 
Here there is an exposure of 15 feet of Red Bank overlain with 5 feet 
of Columbia loam and gravel. It is a reddish-brown, case-hardened 
deposit containing hard pockets or lenses of grayish-green glauconitic 
sand. The upper part is more firmly cemented than the lower. The 
latter grades downward into a loose, greenish glauconite, containing 
only a few ferruginous bands. Another extensive exposure, al- 
though somewhat obscured, is found two miles south of Pivot Bridge. 
The total section at the base is a brownish or a glauconitic sand, 
while the top is reddish-brown, case-hardened sand belonging to the 
Red Bank deposits. Unfortunately the contact between the two 
beds is obscured, but it would seem that there is about 20 feet 
of Navesink at the base of the cliff, and 35 feet of Red Bank above. 
Beside these more instructive exposures, there are a large number of 
lesser importance, which are frequently met with along the borders 
of the Great and Little Bohemia creeks and their tributaries. With- 
out going into details regarding these, it is sufficient to say that their 
distribution indicates a great development of Red Bank in this re- 
gion. Although fossils are occassionally discovered, they are not 
well preserved, and are not numerous. They consist almost entirely 
of marine mollusca. 



164 the coastal plain formations of cecil county 

The Eocene, 
the aquia formation. 

The Aquia formation is the only representative of Eocene deposits 
in Cecil county. It is confined in its distribution to the extreme 
southeastern portion of the region, and is so largely buried beneath 
Pleistocene deposits, that only a small portion of it is visible. The 
name of the formation is derived from Aquia Creek, one of the tribu- 
taries of the Potomac river in Virginia, for in that area, the forma- 
tion is found typically developed. The Aquia formation lies un- 
confcrmably on the underlying Monmouth, and is overlain uncon- 
formable by beds belonging to the Columbia group. 

The materials making up the deposits consist of sand and green- 
sand. The color of fresh exposures varies from a brownish to a 
greenish tint, and certain of them have a very decided green tone. 
This color, however, changes to a brown on weathering. 

The most western outcrop of the Aquia formation of any import- 
ance is in the valley a mile north of Fredericktown. There the for- 
mation is a slightly cemented glauconitic sand, and in fresh exposures 
has a somewhat streaked and mottled appearance, due to the mixing 
of grayish-green and reddish-brown sand. The thickness of the expo- 
sure is about 35 feet and it is underlain by Monmouth and overlain by 
coarse cross-bedded Columbia sand and gravel. The outcrop shows 
quite continuously from this point down the valley to the Sassafras 
river. 

Along the river to the east and west of Fredericktown there is a 
continuous outcrop of Aquia varying from 15 to 20 feet in thickness. 
The best exposures are in the town, where it is found to be very 
similar in appearance to the deposit just described although it does 
not contain as much iron. East of Fredericktown the amount of 
glauconitic and calcareous matter seems to increase and the character 
of the Aquia formation changes so as to resemble what may be de- 
scribed as a pepper and salt appearance. In the stream-cut west of 
Duffy Creek there is a fair exposure of a light greenish-brown sand 
which is very slightly cemented and full of white concretionary 



MARYLAND GEOLOGICAL SURVEY 165 

forms, with here and there some iron, case-hardened material in the 
form of nodules and bands. Towards the town of Sassafras the 
Aquia formation becomes less distinct and finally disappears beneath 
a deposit of Columbia gravel. 

The formation, as a whole, dips toward the southeast at the rate 
of about 20 feet to the mile, and strikes across the country from 
northeast to southwest. A few imperfect casts of marine mollusks 
have been found in the formation. Such fossils as the formation 
has yielded point to its Eocene age. 

The determination of the full extent of the Aquia formation in 
Cecil county has been attended with no little uncertainty. The diffi- 
culty consists in separating the Aquia from the Rancocas formation. 
The latter undoubtedly is present across the border in Delaware 
where the Bryozoan limestone is well developed. In Kent county, 
however, fossil forms which have heretofore been considered as be- 
longing to the Rancocas fauna are found above othei forms, which 
undoubtedly belong to the Aquia period. As the deposits at Fred- 
ericktown contain an Eocene fauna, and as no deposit carrying an 
undoubted Rancocas fauna has been discovered in Cecil county, it 
has seemed best to refer all the greensand beds lying above the Red 
Bank sands and beneath the deposits of the Columbia group to the 
Aquia formation. 

The ]STeocene. 

the lafayette formation. 

The name of this formation was suggested by Lafayette county, in 
Mississippi, where the beds were found to be well developed. The 
age of the Lafayette is problematical. 'No- fossils have, up to the 
present time, been found within its body of sufficient diagnostic char- 
acter to show conclusively where the formation belongs in the geo- 
logical scale. It has been supposed, however, for some time that it 
belongs in the Pliocene. The Lafayette formation, as a whole, is 
developed along the Atlantic coast, either as continuous masses, or as 
isolated remnants from Pennsylvania to South Carolina. In the 
northern portion of the Atlantic Coastal Plain the Lafayette is rep- 



166 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

resented by disconnected remnants or small areas. It is this broken 
feature, which chiefly characterizes its distribution in Cecil county. 
Within this county the Lafayette is developed in two groups of out- 
liers; one of these groups is found on the southern margin of the 
Piedmont, near its contact with the Coastal Plain, between the Sus- 
quehanna and Little Elk Creek. The other group of outliers is 
confined to the peninsula of Elk Neck, and occupies its highest hill- 
tops, extending down its center from near Bacon Hill to Maulden 
Mountain. These outliers are the remnants of a once continuous 
mantle of the Lafayette formation, which probably extended over 
all of Cecil county. They, at the present time occupy the highest 
elevations in the vicinity, but as they are constantly being carried 
away by erosion, their volume is growing less and less. The most 
important localities for Lafayette are found on the highland in the 
vicinity of "Woodlawn, and just east of it across Principio Creek, on 
the elevation between Theodore and Foys Hill. There are also 
scattered outliers extending from Theodore to the eastward toward 
Egg Hill. On Elk Neck some of the highest points of the Hog Hills 
carry a capping of Lafayette. A large area is met with on the hill- 
tops and range of hills just south from here, and also on Black Hill, 
Elk Neck, Bull Mountain and Maulden Mountain. 

The materials of the Lafayette formation were not deposited on 
a perfectly plain surface, but on a. somewhat rolling one, and since 
their deposition, have been raised and somewhat titled toward the 
southeast. The result is that while there is a general decrease in the 
elevation of the base of this formation from the Piedmont to the 
ocean there is also a variation in the height at which the base is found 
even in restricted area, thus: along the Piedmont where the structure 
-of the formation would seem to pre-suppose the same general height 
for the base the formation actually rests on a platform varying from 
460 to 310 feet. These changes, however, do not take place abruptly. 
Along the backbone of Elk Neck the base lies considerably lower 
than on the Piedmont, but as it is further down the dip this change in 
altitude is no more than should be expected. Yet even in this region 
the altitude of the base is Pound to vary between 120 and 200 feet. 



MAE YL AND GEOLOGICAL SURVEY 167 

The materials composing the Lafayette formation consist mostly of 
quartzitic sands and gravels, either loosely held together or united 
more or less firmly with a cement of iron oxide. There are also 
found in places small admixtures of clay which aid in binding the 
otherwise loose sands together. The consistency of the materials varies 
anywhere from loose sand and gravel to conglomerate. Where the iron 
has not succeeded in binding the materials firmly together the face 
of an exposure has the appearance of being case-hardened when dry, 
although somewhat less obdurate when wet. The outliers of Lafay- 
ette are frequently hidden in the midst of thick woods and covered 
over with heavy undergrowth. Where the streams ( have cut into 
them the banks rapidly fall in and are quickly covered with vegetable 
growth. Good exposures are consequently very rare in this forma- 
tion. Only where the material is artificially exposed by the opening 
of pits, is one able to gain a good idea of its internal structure. One 
of these gravel pits is found at a height of 880 feet on M. Marple's 
farm, one mile west of Egg Hill. Here there is a gravel hill which 
has been used for road-material for miles around. The gravel, how- 
ever, is not as coarse and the proportion of pebbles to fine gravel 
and sand is about equal. There is also a little clay mixed in the 
•deposit. Near the top of the hill at a height of about 400 feet there 
is a heavy bed of iron-sandstone and conglomerate, varying from 3 
to 5 feet in thickness. This is so firmly cemented that it has been 
used for building purposes. 

The best exposure of the Lafayette formation is on the highway 
one mile south of Bay View. Here, in a large pit which has been 
opened for road-material, there is an 18-foot exposure of coarse gravel 
in which some of the pebbles are between one and two inches in diame- 
ter, and are mixed with brownish-yellow sand, containing a little 
clay. The proportion of pebbles to very fine sand is about 2 to 1. 
The whole is colored brownish by iron, but in no place is it cemented. 
The grade of coarseness of the gravel is remarkably uniform from 
the bottom to the top of the exposure. 

On Elk Neck there are no good exposures in the Lafayette for- 
mation. There is abundant proof, however, that the formation is 



168 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

represented on the hilltops indicated on the map from the abundance 
of gravel in those localities. Most of the deposits of Lafayette on 
Elk Neck are characterized by indurated blocks of conglomerate, 
ranging from cobbles up to masses a foot in thickness and weighing 
several hundred pounds. These have evidently broken away from 
more or less continuous bands of conglomerate, which formerly ex- 
tended over the summit region of Elk Neck, and although obscured at 
the present time, no doubt still exist on many of the hilltops. 

The thickness of the Lafayette formation is a matter difficult to 
determine. Not only is it impossible at all times to ascertain the 
location of the contact between the base of the Lafayette and the 
formation on Avhich it rests, but the slight irregularities in the con- 
tact indicate that the formation is in the nature of a cover or veneer, 
and to assume that its base has the same altitude in the center of the 
hill which it has on the sides would seem perhaps to be somewhat ven- 
turesome and unwarranted. There cannot, however, be a great dif- 
ference between the two. If the topography of Bull Mountain is 
correct the thickness of the Lafayette in that locality is a hundred 
feet, and the same is true of Black Hill and the large area to the 
southeast. The gravel cappings of the Hog Hills are not quite so 
thick, and the areas of the Piedmont Plateau do not range much above 
40 feet in thickness, and probably do not average even that amount. 
It is possible that the elevations of Bull Mountain and Black Hill 
have not been accurately determined, and that the base of the La- 
fayette formation in these two localities is also somewhat incorrect, 
in which case the thickness of the formation would be reduced. In 
the absence, however, of absolute knowledge on this point it is safe 
to say that the Lafayette in Cecil county is often very thin, and 
never exceeds 100 feet in thickness. The maximum thickness lies 
somewhere between 80 and 100 feet. The strike of the Lafayette 
gravels is like that of the other Coastal Plain formations, from north- 
east to southwest. The dip of the formation is to the southeast, but 
its amount is difficult if not impossible to determine accurately. 
There is no doubt that the general base of the formation on Elk Neck 
is considerably lower than that of the same formation on the Pied- 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XV. 




Fig. i.— view showing sunderland terraces with lafayette in the foreground. 





•Fig. 2.— top of THE WICOMICO formation at turkey point. 



GEOLOGICAL SECTIONS IN CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 169 

mont Plateau, but as the base occupies a changing elevation in both 
districts it is impossible to fix on any one locality as the typical posi- 
tion. It would seem that 400 feet was a fair average for the eleva- 
tion of the base on the Piedmont Plateau and 200 feet on Elk Neck. 
If these averages are approximately correct they indicate a dip of the 
Lafayette formation to the southeast at a rate of 25 feet per mile. 
It will be sufficient to say that the dip is probably not less than 20 
feet, nor more than 30 feet per mile. 

The Pleistocene. 

the columbia group. 

The Columbia Group is the name applied to a series of beds of 
clay, loam, sand and gravel, which are stratigraphically younger than, 
and lie topographically below the Lafayette formation. They are 
Pleistocene in age and are the last formations made in the region be- 
fore the recent deposits. Several years ago Mr. W J McGee out- 
lined the geology of the beds which now constitute the Columbia 
group, and gave to them the name Columbia formation because of 
their typical development within the District of Columbia. Subse- 
quent study, however, has shown that the beds are divisible into three 
well-defined formations, which have received separate names and the 
term Columbia is now retained to designate the group. The forma- 
tions which constitute the Columbia group are as follows, beginning 
with the oldest: the Sunderland, the Wicomico and the Talbot. A 
more definite correlation than this is not possible at the present time, 
as the determination of this question depends on the relation of the 
respective formations to the glacial deposits of neighboring regions. 
"When this relation has been more carefully worked out, no doubt the 
correlation can be determined more accurately between the various 
members of the Columbia group and the various epochs which have 
been proposed in the Pleistocene period. It is possible that the Tal- 
bot may be in part recent. The formations of the Columbia group 
lie unconformably on whatever rocks are beneath them. They con- 
sist of clays, loams, sands and gravels, which run in irregular beds, 



170 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

or are developed in lenses and are mixed together in varying 
amounts. Up to the present time no animal remains have been dis- 
covered in them within Cecil county, but an abundance of vegetable 
remains has been met with in old lagoon deposits belonging to the 
Talbot formation. 

The various members' of the Columbia group are developed as ter- 
races, lying one above the other, and are horizontal in position with 
the exception of a slight initial dip toward the waters out of which 
they have been raised. As the beds lie in this horizontal position it is 
out of place to speak of them as striking across the county. The 
most that can be said is that they occupy most of its southern two- 
thirds, and their northward margin crosses the State from north- 
east to southwest in a line approximately coincident with that of the 
Baltimore and Ohio Railroad. 

The Sunderland Formation. 

The Sunderland formation has been so called from its typical de- 
velopment near the hamlet of Sunderland in Calvert county, Mary- 
land. It consists of a wave-built terrace composed of clay, loam, sand 
and gravel, which were deposited by the waves of the Atlantic Ocean 
when the county stood at a lower level than it does to-day. Its base 
lies at about 90 feet, and its upper limit at a height varying from 
about 160 to 180 feet. It has suffered so much from erosion since 
the time of its deposition that only a remnant is now left to indicate 
its former distribution. It does not exist on the Eastern Shore di- 
vision of the Atlantic Coastal Plain, but is found as an irregular 
terrace much dissected by waterways, and seldom exceeding a mile 
in width, extending from the Susquehanna river to Lesley, and 
mostly confined between the Philadelphia, Wilmington and Baltimore 
and Baltimore and Ohio railroads. It is also represented by outliers 
between Iron Hill and Northeast River. On Elk Neck the Sunder- 
land formation is represented by a few outliers in the vicinity of the 
Hog Hills and another group of outliers in the vicinity of Elk Neck 
in the southern half of the peninsula. 

Although the base of the Sunderland formation is somewhat Lrregu- 



MARYLAND GEOLOGICAL SURVEY 171 

lar, yet the formation as a whole does not appear to dip in any one 
direction, but to lie in the same horizontal position in which it was 
laid down, although elevated as a whole 100 feet or more above its 
original position. No fossils have been discovered in the Sunderland 
formation in Cecil county. 

The Wicomico Formation. 

The next younger formation is the Wicomico. This formation re- 
ceived its name from the Wicomico River in Charles and St. Mary's 
counties, Maryland. It is a series of clays, loam, sands and gravels, 
which were deposited by the Atlantic Ocean in the form of a terrace 
and off-shore deposit when Cecil county stood at a lower level than it 
occupies to-day. This deposit was formed at a comparatively re- 
cent date, and therefore has not suffered from erosion to the extent 
of the previously described Sunderland. It is the most widespread 
and conspicuous formation of Cecil county. It occupies the entire 
surface of the Eastern Shore above 35 or 40 feet, and is developed 
as a terrace usually a mile or more in width, extending around the 
borders of Elk Neck and Northeast River just outside of the margin 
of the Sunderland terrace. Its limits therefore are between 90 to 
100 feet and 30 to 40 feet. Although it has suffered much less 
from erosion than has the Sunderland formation, still the rivers have 
opened up deep valleys within it and some of the shorter streams with 
quick return to the Bay have succeeded in carrying it partially away. 
This latter fact is demonstrated on Elk Neck just west of the Black 
Hill, in the region of Bull Mountain and also on the same peninsula 
in the vicinity of Northeast. 

At numerous points in the vicinity of the head of Chesapeake Bay, 
huge boulders have been found, not only imbedded in the body of the 
deposit, but lying scattered about on its surface. These, as McGee 
has shown, are thickest in the vicinity of the shore-line of Chesapeake 
Bay, and diminish gradually in abundance in all directions. A typi- 
cal section of the Wicomico formation may be seen at Turkey Point 
at the southern extremity of Elk Neck. Plate XV, Eig. 2. 



172 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY . 

Section of the Wicomico Formation at Turkey Point. 

Feet Inches 

Sandy clay 10 

Coarse gravel layer, with boulder bed at base 15 

Gravel and clay pebbles, containing black bands 3 

Arkosic sand and coarse gravel 4 

Brownish clay sand 1 

Coarse arkosic sand and clay pebbles, containing black bands 

and spots 18 

White clay 1 

Quartz pebbles . . 3 

Coarse cross-bedded, arkosic, reddish-brown sand 15 

Variegated clay 3 

Patapsco 

The surface of the Wicomico formation slopes gently toward the 
Atlantic Ocean. It is not at all certain, however, that this represents 
a differential tilting of the formation, but more likely should be re- 
garded as the natural attitude of the surface when it was deposited, 
and represents a gradual falling away of the sea-bottom from the 
shore toward deeper water. No fossils have as yet been discovered in 
this formation in Cecil county. 

The Talbot Formation. 

This formation is named from its typical development in Talbot 
county, Maryland. In Cecil county it consists of a series of clays, 
Loams, sands and gravels which are built up as a terrace, extending 
from tide to a height of 30 or 40 feet. It is developed as a narrow 
fringe, seldom exceeding a quarter to half a mile in width, extending 
around the entire border of Cecil county and well up the estuaries. 
Being the youngest formation of the Columbia group it has suffered 
least from erosion, and although streams have opened up their courses 
across it, still it is seldom absent. 

With the exception of a general uplift the attitude of the Talbot 
formation seems to be essentially the same as when deposited. ISTo 
tilting has been detected. The gentle slope of the surface toward 
Chesapeake Bay is regarded as the natural attitude of the formation 
which it assumed during deposition as it sloped gently from shore 
to deeper water. 



MARYLAND GEOLOGICAL SURVEY 173 

This is the only formation of the Columbia group which has yield- 
ed fossils of any kind in Cecil county. There are developed in the 
Talbot formation lenses of drab-colored clay, carrying stumps, roots 
and knees of cypress, together with leaves and other vegetable re- 
mains. 

Interpretation of the Geological Record. 
sedimentary record of the crystalline rocks. 
The crystalline rocks of Cecil county have suffered so many dis- 
turbances since their formation that they now almost defy interpre- 
tation, and their history is consequently imperfect and fragmentary. 
The oldest rock in the series, and therefore the most ancient in Cecil 
county appears to be the mica-gneiss, which is either pre-Cambrian 
or Cambrian-Silurian in age. This mica-gneiss is the product of meta- 
morphism acting upon finely conglomeratic, arkosic, sandy and argil- 
laceous sediments. 

These materials were probably accumulated just off-shore during 
the denudation and subsidence of a pre-Cambrian continent. Subse- 
quently this sedimentary series suffered elevation with severe fold- 
ing, intrusion by igneous masses and metamorphism. Into this sedi- 
mentary formation eruptive masses have been intruded during periods 
when these were thicker than at present or more heavily covered with 
sediments which were later removed by erosion. These igneous rocks 
were apparently injected during three distinct periods of disturbances, 
and were introduced in the order— granite ; rhyolite; gabbro, pyroxen- 
ites and peridotites. These eruptions were accompanied by differ- 
entiation and solidification of the magmas. Then or subsequently, 
the rocks suffered metamorphism, which has produced a laminated or 
gneissic structure in the granite and gabbro and converted the pyrox- 
enites and peridotites into amphibole schists, serpentines and steatite 

schists. 

This early period of sedimentation and intrusion of igneous intru- 
sives was followed by long ages during which the land probably stood 
above sea-level, a victim to the long continued action of subaerial denu- 
dation. If at any time during the long interval between the deposi- 



174 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

tion of the sediments now represented by the mica-gneiss and the de- 
position of the Triassic sediments the land was below the waters 
of the ocean, the evidences of such submergence have all been re- 
moved from the area of Cecil county. 

SEDIMENTARY RECORD OF THE POTOMAC GROUP. 

With the opening of Potomac time, a new chapter in the develop- 
ment of Cecil county began. The deposits which have recorded its 
geological history from that time down to the present, are all uncon- 
solidated, and collectively constitute the Coastal Plain formations. 
They show, as a whole, a remarkable unsteadiness of the continental 
border, for Cecil county has been either in part or as a whole, lifted 
above the ocean level and depressed beneath the sea, not less than ten 
times, and possibly many more. These oscillations of the coast-line 
were not confined to Cecil county but affected also neighboring re- 
gions of great extent. The disturbances have been recorded as un- 
conformities between the various formations. The unconformities, 
however, are with few exceptions not striking to the eye, but are only 
to be observed when the region is studied as a whole, and the indi- 
vidual beds traced foot by foot over the entire district where they 
are developed. 

The sedimentary record of the Potomac group opens with the depo- 
sition of the Patuxent formation. This deposit consists of clay, sand, 
gravel and arkose. In the laminae of clay and sand are numerous 
remains of plants which flourished on land while the sediments were 
being deposited off-shore in the water. The materials which go to 
make up the body of the Patuxent formation are frequently cross- 
bedded, and change rapidly in their composition, not only vertically 
but also horizontally. The whole constitution of the formation indi- 
cates that it was deposited in shallow water qoI far from shore, and 
where currents were constantly changing in intensity. At the close 
of Patuxenl time Cecil county was elevated above the waters which 
had deposited the Patuxent formation. The extent of this elevation 
will never be known, for the unconformity is now only in part visible. 
How far it runs out under the Eastern Shore is of course a question 



MARYLAND GEOLOGICAL SURVEY 175 

which has not been determined. That the elevation did extend far to 
the east beyond the present borders of the Piedmont Plateau seems 
however, to be an hypothesis which almost amounts to a certainty. 

A vast amount of erosion followed the uplift of the Patuxent forma- 
tion before the region was again lowered beneath the sea. The 
formation which succeeds the Patuxent is known as the Patapsco. 
In regions further to the south, a formation known as the Arundel 
has been found interpolated between the Patuxent and Patapsco for- 
mations; but in Cecil county its presence is doubtful. The 
Patapsco formation is composed of' the same sort of materials as are 
found in the Patuxent formation, with the exception of arkose. Not 
only is there a similarity in materials but there is also 1 a great likeness 
in the way in which the different sorts of ingredients are assembled. 
There is the same rapid change, both horizontally and vertically, as 
was found to exist in the Patuxent formation, and, consequently, like 
inferences must be drawn regarding its mode of formation. The 
Patapsco therefore indicates a repetition of the conditions which 
existed during Patuxent time. They were off-shore deposits made in 
shallow water by shifting currents of varying intensity. There is, 
however, a striking change in the character of the plant remains. In 
the Patuxent, few dicotyledons have as yet been discovered; while in 
the Patapsco, a large number of dicotyledons have been found. The 
meaning of this difference in the fossil flora has led to much discus- 
sion ; it seems probable, however, as suggested by Professor Clark and 
Mr. Bibbins, 1 that the stratigraphic break between the Patuxent and 
Patapsco formations indicates a lapse of time of long duration, during 
which the flora became greatly modified. The evidence, to be sure, 
is incomplete, but the few and primitive dicotyledons in the Patux- 
ent formation suggest the possibility of the Jurassic age of that form- 
ation, while the presence of Lower Cretaceous dicotyledons in the 
Patapsco, places the age of that formation beyond question. Further 
south in certain other counties of Maryland, remains of animals which 
Professor O. C. Marsh referred to the Jurassic, are confined to the 

1 The Stratigraphy of the Potomac Group in Maryland. Jour, of Geol., vol. v, pp. 
479-506, Chicago, 1897. 



176 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

portion of the Potomac group lying beneath the Patapsco formation. 
On the strength of this evidence the Patuxent formation has been 
tentatively referred to the Jurassic period. 

The Patapsco cycle of sedimentation came to a close with the up- 
lifting of Cecil county once more above the surface of the water. 
This uplift was of sufficient duration to permit another extensive de- 
nudation of the surface before the region sank again beneath the 
waves. This submergence ushered in the Karitan cycle of sedimen- 
tation, during which the Raritan formation was deposited. This 
formation, like the two preceding, was also an estuarian deposit laid 
down in shallow water in the midst of currents constantly changing 
in direction and intensity. Its plant remains embraced, like the 
preceding formation, both endogens and exogens, the exogens exhibit- 
ing strongly marked modern affinities. The re-elevation of the region 
closed the Raritan cycle of deposition and brought that formation in 
turn, above the level of the ocean, and subjected it to the destructive 
work of sub-aerial erosion. 

Before leaving the record of the formations belonging to the Po- 
tomac group, a word should be said regarding the nature of the body 
of water in which they were deposited. After a careful study of the 
formations, not only in Cecil county, but in neighboring regions to 
the north and south, it has been determined that the sediments are not 
such as can be ascribed to deposits formed in the open ocean. They 
partake rather of the character of sediments laid down in bodies of 
brackish water where the direct influence of the sea has been elimi- 
nated. It is believed, therefore, that the formations of the Potomac 
group were deposited in a sound or an estuary of brackish water, 
which was separated from the main ocean by a land barrier. The 
position of this land mass has given rise to some discussion, and from 
the nature of the case, can never be definitely determined; but it 
probably was located somewhat east of the present Atlantic coast-line. 

SEDIMENTARY RECORD OF THE UPPER CRETACEOUS FORMATIONS. 

The erosion interval which followed the uplift of the Raritan for- 
mation was brought to a close by the sinking of Cecil county <>nce 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XVI. 




/■; ■'■""'• /"*-. -,», 




FlG. 1.— FOSSIL TREE STUMP IN TALBOT FORMATION, BOHEMIA RIVER. 




Fig. 2.-SECTION IN THE TALBOT FORMATION, NEAR PERRYVILLE. 
GEOLOGICAL SECTIONS IN CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 



177 



more beneath the water. This submergence differed from those 
which had occurred in Potomac time in that the county was lowered, 
not beneath a lagoon, but beneath the open Atlantic Ocean. The 
deposits which compose the Upper Cretaceous formations consist of 
clay, sand and greensand. These materials, although thej are found 
to change gradually from one area to another, yet maintain re- 
markable uniformity, both vertically and horizontally, over great 
areas. In New Jersey the predominant feature of this group is the 
presence of vast beds of greensand. In Cecil county, however, and 
the same is true southward, greensand has largely given place to ordi- 
nary quartz sand, both fine and coarse. This change in the char- 
acter of the materials would seem to indicate that the deposits in Cecil 
county were deposited nearer the old shore-line, and in shallower 
water than those further to the north. Fossil remains, such as they 
are, consist of marine animals. They are not numerous and are un- 
fortunately in a poor state of preservation. The evidence, as a whole, 
points to the fact that the formations of the Upper Cretaceous were 
deposited in the open ocean at moderate depths. 

The two formations, Matawan and Monmouth, which represent the 
Upper Cretaceous in Cecil county, are not separated by an unconform- 
ity as are the formations of the Potomac group but pass into each 
other with imperceptible gradations. From this it appears that the 
oscillations which disturbed the region during Potomac time ceased 
during Upper Cretaceous time; or if they were present, were not of 
sufficient amplitude to be recorded by those portions of the Upper 
Cretaceous deposits now remaining. This cycle of deposition was 
brought to a close by an elevation of the country above the level of 
the Atlantic Ocean. A long period of erosion followed this uplift, 
which was finally brought to a close by the submergence of the re- 
gion once more. 

SEDIMENTARY RECORD OF THE AQUIA FORMATION. 

The submergence which brought Cecil county once more beneath 

the Atlantic Ocean ushered in the cycle during which the Aquia 

formation of Eocene age was deposited. This, in many of its char- 
12 



178 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

acteristics, resembles closely the preceding deposits. The materials 
are mainly sand and greensand, and the fossils which have been dis- 
covered, are marine. The evidence then would seem to indicate 
that the conditions which existed during the cycle when the Upper 
Cretaceous formations were deposited, were repeated, when the 
Aquia formation was made, for it seems to have been laid down off- 
shore on the bed of the open ocean in water of moderate depths. An 
elevation of the region brought this formation in its turn above the 
ocean, and closed the cycle of its deposition. 

SEDIMENTARY RECORD OF THE LAFAY'ETTE FORMATION. 

The next younger formation which is present in Cecil county, is 
the Lafayette, although in some of the neighboring counties a number 
of formations belonging to the Miocene period are interpolated be- 
tween the Aquia and the Lafayette. No record of these Miocene 
beds have been discovered in Cecil county, and if they ever existed 
there, they have been entirely removed. The depression, which 
opened the Lafayette period of deposition carried the whole of Cecil 
county beneath the sea; probably not even the highest points in its 
topography remained above the surface of the water. The cycle of 
deposition which followed was of sufficient duration to bury the an- 
cient surface of Cecil county under a heavy load of clay, sand and 
gravel. The source of these materials was in the Piedmont Plateau 
and the Appalachian Mountains. The former appears to have been 
undergoing sub-aerial decay for a long time, so that its surface was 
covered with a mantle derived from its disintegrated crystalline rocks. 
In such a mantle, the more easily decayed rocks would be reduced to 
clay and sand, while the more obdurate veins of quartz would yield 
;i large number of loose stones lying in confusion on the surface. 

With the advance of the Lafayette sea, the quartz fragments were 
concentrated by the waves on the beach, while the finer particles were 
swept out by the undertow and deposited in deeper water. To the 
whole was added such material as could endure the journey from the 
more distanl mountain regions. After Cecil county had received a 



MARYLAND GEOLOGICAL SURVEY 179 

mantle of Lafayette gravel it was once more elevated above the level 
of the ocean and remained in this position for a considerable period. 
It is probable that the drainage which established itself on the La- 
fayette surface, worked its way downward through the body of that 
formation and finally became fixed in the underlying crystalline rocks, 
and as explained above, the origin of the curious river system of the 
Piedmont Plateau in Cecil county is perhaps to be ascribed to the 
erosion which followed the uplift of the Lafayette formation. 

SEDIMENTARY RECORD OE THE COLUMBIA GROUP. 

At the close of the post-Lafayette period of erosion, one of the 
most interesting chapters of the geologic history of Cecil county was 
commenced. The unsteadiness of the coast-line, which had manifested 
itself repeatedly during Potomac, Upper Cretaceous, Aquia and La- 
fayette time, now became intensified, and during Columbia time, a 
remarkable series of oscillations have been recorded in the deposits 
of that group. These oscillations are known to have affected the 
North Atlantic Coastal Plain, and many and possibly all of them will 
ultimately be recognized in the Coastal Plain further south. As the 
southeastern two-thirds of Cecil county falls within the province of 
the North Atlantic Coastal Plain, it shared in all these movements, 
and each oscillation which is recorded in other portions of the Coastal 
Plain is here also represented by its distinct formation. 

These formations, to which the names Sunderland, AVicomico and 
Talbot have been applied, arc developed in terraces lying one above 
the other in a vertical range from tide to an altitude of about 180 
feet. Beneath these three terraces, there is forming to-day a fourth 
which extends from high-tide downwards beneath the waves to deeper 
water. 

The key to the interpretation of these terraces is secured by study- 
ing the manner in which this recent terrace is forming. At the 
present time the waves of the Atlantic Ocean and Chesapeake Bay 
are engaged in tearing away the land along their shores and in de- 
positing the detritus on a submarine platform or terrace. This ter- 



180 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

race is everywhere present and may be found not only along the 
exposed shores but also passing up the estuaries to their heads. The 
materials which compose them are extremely variable. Along the 
unbroken coast the detritus has a local character, while near river 
mouths, the terrace is composed of the debris contributed from the 
river basin. 

In addition to building a terrace, the waves of the Atlantic and 
the Chesapeake are cutting a sea-cliff along their coast-line. The 
height of this cliff depends not only on the force of the breakers but 
also on the relief of the land against which the waves beat. A low 
coast-line yields a low sea-cliff, and a bold coast-line, a high one, and 
each passes into the other as often and as rapidly as the topography 
changes, so that as one travels along the shore of Chesapeake Bay 
high cliffs and low depressions are passed successively. The wave- 
built terraces and the wave-cut cliffs are important features along the 
entire extent of the Bay shore, and should be sought for wherever 
other terrace surfaces are studied. It must, however, be borne in 
mind that there are places along the Bay shore where the sea-cliff is 
absent, or so low that it does not form a conspicuous feature in the 
topography. In addition to these features, bars, spits and other wave 
and current-built formations of a similar character are frequently 
met with. 

If the present coast-line should be elevated, the submerged plat- 
form which is now forming would appear as a well-defined terrace of 
variable width with a surface gently sloping toward the water. This 
surface would fringe the entire Atlantic and Bay shores as well as 
those of all the estuaries. The sea-cliff would at first be sharp and 
easily distinguished, but as time passed, the least conspicuous portions 
would gradually yield to the levelling influences of erosion, such as 
soil-creep, plant roots and cultivation, and might gradually disappear 
altogether. Erosion would also destroy in large measure the original 
continuity of the formation, but as long as portions of it remained, 
the old surface could be reconstructed and the history of its origin 
di lei-mined. 

If the topographic and geologic features which are associated with 



MARYLAND GEOLOGICAL SURVEY 181 

the terrace now forming are compared with those which accompany 
the various terraces of the Columbia group, the analogy is found to 
be so striking that the conclusion regarding a common origin of both 
is irresistible, and there can be no reasonable doubt that the mode of 
formation of the modern terrace furnishes the key to the interpreta- 
tion of the ancient. 

The earliest of these ancient terraces of the Columbia group has 
been assigned to the Sunderland formation. This terrace occupies 
the highest topographic position of the series, and ranges from an 
altitude of 90 to about 180 feet. 

The subsidence of the Atlantic Coastal Plain, which carried down 
the southern half of Cecil county checked somewhat the erosion which 
had been destroying the Lafayette deposits and caused the deposition 
of the Sunderland formation. As Cecil county slowly sank beneath 
the water, the shore of the advancing Atlantic gradually crept further 
and further westward, until it finally came to rest in a circuitous line 
extending from near Erenchtown on the Susquehanna river northeast 
to Belvidere, approximately in the position now occupied by the Bal- 
timore and Ohio Railroad. From here the coast-line passed south of 
Eoys Hill and on to Leslie; it then turned southward and encircled 
the western, southern and eastern flanks of the Hog Hills, and then 
northward again to Childs, Singerly, Banks and Iron Hill where it 
passed out of the State. Grays Hill and the highest portions of Elk 
Neck south of the Hog Hills rose above the sea as islands. How 
long the sea. remained in this position is not definitely known, but it 
is known that it stood there long enough to cut a well-pronounced 
sea-cliff along a large portion of its border. This ancient sea-cliff 
has since suffered greatly from erosion and in many places is nearly 
obliterated but in other localities may be distinctly seen to-day form- 
ing a prominent feature in the local topography. Among the best 
localities for viewing this ancient sea-cliff may be mentioned the 
abrupt rise one-half mile north of Aiken extending from the Blythe- 
dale road eastward toward Jackson, again around the flanks of Eoys 
Hill, near Leslie, on the slopes of the Hog Hills, at Elk Neck and 
Bull Mountain. The scarp line north of Elkton in the vicinity of 



1 M' THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

Singerly, Baldwin and Iron Hill is not a conspicuous feature, although 
a gentle rise suggests the former position of the old shore. 

While the formation of the Sunderland terrace was still in progress 
the region rose above the surface of the Atlantic Ocean and ero- 
sion began vigorously to carry away the loose sands and gravels which 
bad just been laid down. How extensive this uplift was it is now 
impossible to say. It is also equally difficult to determine its dura- 
tion, but it was of sufficient length to permit the destruction of a large 
portion of the Sunderland formation. When the country sank again 
and permitted the waters of the Atlantic to encroach once more over 
the sinking region, the advancing waves completed the work of the 
rivers and leveled off whatever prominences were left unreduced. 
During this Wicomico depression, however, Cecil county did not sub- 
side to the depth which it did during the previous submergence and 
the shore-line finally came to rest at a line a little to the south of that 
occupied by the Atlantic during Sunderland time. In a rough 
way, this Wicomico shore-line corresponded with the position now 
occupied by the Philadelphia, Wilmington and Baltimore Railroad 
from the Susquehanna to Northeast. From Northeast it turned 
southward to encircle the high land running down the middle of Elk 
Neck, then northward again to within one-half mile of Childs. From 
this point it passed southeast to within half a mile of Elkton and then 
northeastward. Grays Hill again rose above the water as an island 
and was encircled by the Wicomico shore-line. With this single ex- 
ception, the entire Eastern Shore was submerged. The maximum 
advance of the Atlantic Ocean during Wicomico time is well shown 
in a pronounced sea-cliff which separates the Wicomico formation 
from older ones lying above it. This has suffered less from erosion 
than the Sunderland sea-cliff and may be distinctly seen throughout 
almost its entire extent. Notable examples are between Aiken and 
Principio Station, in the vicinity of Northeast, along the eastern slope 
of Elk Neck and around the margins of Grays Hill. Throughout the 
county, the Wicomico terrace ends, and the sea-cliff cut by the waves 
of the Wicomico sea begins, at about the 90- or 100-foot contour. 
\\ bile the Wicomico formation was still forming, Cecil county was 



MARYLAND GEOLOGICAL SURVEY 183 

raised above the level of the ocean and the formation subjected to 
stream erosion. The region, however, did not long remain in this 
position but before erosion had progressed extensively, the county 
was submerged once more to a depth of about 40 to 45 feet lower 
than the position it now occupies. 

This was the time of the deposit of the Talbot terrace. The sub- 
sidence which initiated the deposition of the Talbot terrace was com- 
paratively slight and was not sufficient to depress the Eastern Shore 
and admit the Atlantic Ocean. Cecil county during Talbot time dif- 
fered from its present appearance only in an enlargement of the 
borders of Chesapeake Bay and its estuaries. The land did not re- 
main in this position long enough to permit the carving of a very 
pronounced sea-cliff although a low one may be seen separating the 
Talbot from the Wicomico terrace. This is particularly well seen 
along the banks of the Elk and Northeast rivers. In the region of 
Elkton, the Wicomico terrace has been, in a great measure, removed 
and the Talbot has been deposited in its place. The abrupt rise in 
the topography just north of Elkton is a scarp-line cut by the Wi- 
comico sea and accentuated by the waves of the Talbot sea. 

Within the Talbot formation, there are a number of lenses of drab- 
colored clay and two of these are of special interest in that they bear 
remains of plants. One of these plant beds is located about a mile 
above the mouth of Bohemia Creek on the north side of Veazey 
Neck. In this locality, a large cypress stump about five feet in diame- 
ter is exposed on the beach at mean tide-level. The stump, which is 
in place, is changing to lignite and is nearly covered with beach sand, 
but its roots are still imbedded where they grew in a mass of dark- 
colored peat-bearing clay. The base of this peat bed is not visible, 
but it, without doubt, rests unconformably in a hollow in the Rari- 
tan, for that formation rises to view from beneath the beach a few 
rods away. In the bank above the beach the same peat bed which 
carries the cypress stump is continued upward for six feet when it is 
abruptly overlain with three feet of sand and gravel, which in turn 
grades upward into loam. The other locality in which plant remains 
have been found is situated on the shore of Elk River above the mouth 



184 THE COASTAL PLAIN FOKMATIONS OF CECIL COUNTY 

of Pond Creek. Several stumps of cypress are there exposed on the 
beach at about the level of high tide. They are in place, and are 
surrounded and imbedded in a peat deposit about six feet in thick- 
ness. This peat bed is overlain by five feet of sand and gravel 
which grade up into nine feet of loam. These two sections are most 
suggestive, but in order to bring out their full significance it would be 
necessary to describe a number of similar deposits which occur in the 
various localities within the State of Maryland. 

Along the shore of Chesapeake Bay and the lower courses of many 
of its estuaries there occur at intervals deposits of greenish-blue clay 
developed as lenses in the body of the Talbot formation. Usually the 
base of the clay is not visible but its stratigraphic relations are such as 
to leave no doubt that it, or a thin gravel bed on which it occasion- 
ally rests, is unconformable on whatever lies beneath. The upper 
surface of these clay lenses is everywhere abruptly terminated by a 
bed of coarse sand or gravel which grades upwards into loam and at 
its contact with the clay strongly suggests an unconformity. These 
clay lenses are in some localities devoid of fossils but in others they 
contain remains of marine and estuarine animals and land plants. 
Many localities for these clays are already known and as exploration 
advances new ones are frequently discovered. Some of the more 
typical exposures will now be described. 

Along the shore, about a mile below Bodkin Point, Anne Arundel 
county, the variegated clays of the Raritan formation are finely ex- 
posed in a cliff some thirty feet in height. These clays occupy the 
greater portion of the section and carry an abundance of lignite more 
or less incrusted with crystals of pyrite. Sands and gravels of the 
Talbot formation unconformably overlie the clays and constitute the 
upper portion of the cliff. Half a mile further south the cliff still 
maintains its former height, but the section has changed. Some 
ancient stream must have established its valley on the Raritan sand, 
for here the surface of that formation, like a great concave depres- 
sion, passes gradually beneath the bench to appear again in the cliff 
ii hundred and fifty yards to the south. In this hollow, lying uncon- 
formablv on the Raritan formation, is a bed of dark-colored clay 



MARYLAND GEOLOGICAL SURVEY 



185 



about fifteen feet thick. Bluish and greenish tinted bands of clay 
relieve somewhat the somber aspect of this formation, and at about 
its middle portion it carries a bed of peat. But its most striking fea- 
ture is the presence of huge fossil cypress knees and stumps which are 
imbedded in its lower portion. These stumps vary in diameter from 
two to over ten feet, and after the removal of the surrounding clay, 
stand out prominently in the position in which they must have grown. 
Mr. A. Bibbins, to whom the author is indebted for notes on these 
deposits, has counted thirty-two of these stumps which were visible 
at one time, and also reports finding worm-eaten beechnuts intimately 
associated with cypress cones near the base of the formation. Sands 
and gravels of the Talbot formation overlie the whole. Immediately 
south of this outcrop the dark-colored clays are temporarily replaced 
by the Karitan formation, but they appear again a little further down 
the shore, and afford a good and almost unbroken exposure for about 
a mile. The thickness of the clay in this locality is at first about ten 
or twelve feet, but it gradually becomes thinner southward and finally 
disappears altogether. Casts of Unio shells and not vegetable re- 
mains, are its predominant fossils, while, like the beds containing the 
cypress swamp, it overlies the Raritan formation unconformably, 
and is itself abruptly buried beneath Talbot sands and gravel. 

Another locality of these deposits is on the Bay shore, about a 
mile northeast of Drum Point. Here, at the base of a cliff about 
thirty feet high, is a two-foot bed of dark, chocolate-colored clay carry- 
ing gnarled and twisted sticks protruding in every direction from 
the material in which they are imbedded. Above this occurs a thin 
seam of lignite one and a half feet thick, which in turn is overlain 
with about five feet of slate-colored clay. At this point the continuity 
of the deposit is interrupted by a series of sands, clays and gravels 
belonging to the Talbot formation, which extend upward to the top of 
the cliff. Although the base of this lignitic clay series is buried be- 
neath beach sands, field relations lead to the conclusion that the de- 
posit is very much younger than the Miocene clays on which it rests 
unconformably. A similar section is to be seen on the Patuxent 
river, about a mile below Sollers Landing. Large stumps here pro- 



186 THE COASTAL PLAIN FOEMATIONS OF CECIL COUNTY 

trude from a dark, basal clay bed, some five feet in thickness, which 
is covered by three feet of sand, and this again is buried beneath ten 
feet of 'Fall mt -and and gravel. The relations of the basal clay to the 
underlying Miocene is again obscure, but indications point to an un- 
conformity. Another section is exposed along the shore one and 
one-half miles northwest of Cedar Point, where a thin bed of drab 
clay carrving vegetable remains is overlain abruptly with sands and 
gravels. Its contact with the Miocene is again unfortunately obscure. 
At the localities just described no animal remains have been discov- 
ered, but on the north bank of the Potomac, about half way between 
St. Mary's River and Breton Bay, there is a deposit of lead-colored 
clay, exposed for a quarter of a mile along the shore. It is buried 
at each end as well as above by sands and gravels and carries both 
lignite and Gnathodon cuneata Conrad. Although the description 
given by Conrad is somewhat vague, it is highly probable that he 
visited this locality and collected specimens of the fossils. Two more 
localities still remain to be mentioned, Cornfield Harbor, and its 
companion deposit exposed five and a half miles south of Cedar Point 
on the Bay shore. Conrad was well acquainted with these deposits 
and to the former he devoted special attention. Each is about ten 
feet thick, occurs at the base of a low cliff, is composed mostly of a 
dark, lead-colored clay, and is overlain abruptly with Talbot sand and 
gravel, while unconformity on the Miocene is beautifully shown at 
the base of the Bay shore section. A number of fossils have been 
described from the Cornfield Harbor locality, among which are Ostrea 
virginica Gmelin, Area ponderosa Say, Area transversa Say, Venus 
mercenaria Linn., Mya arenaria Linn., Pholas costata Linn., Crepi- 
dula plana Say, Natica duplicata Say, Busy con carica Gmelin. In 
this exposure the lower four feet of clay carries the marine forms 
and above this there are two feet of sandy clay literally packed with 
Ostrea virginica. These same general relations hold for the similar 
deposits south of Cedar Point. 

The stratigraphic relation of these lenses of clay which are surely 
unconformable on the underlying herniation and apparently so with the 
overlying sand and loams of the Talbot formation is a problem which 



MARYLAND GEOLOGICAL SURVEY 



187 



engaged the attention of the author until it appeared that the appar- 
ent unconformity with the Talbot, although in a sense real, does not, 
however, represent an appreciable lapse of time and that therefore 
the clay lenses are actually a part of that formation. In order to un- 
derstand more clearly what is believed to have taken place, these clay 
deposits should be divided into two groups, those which carry plant 
remains constituting one, and those containing marine and brackish- 




Fig. 8. Diagram showing pre-Talbot valley. 

water fossils the other. Such as are devoid of fossils may belong to 
either one of the groups according to their situation but probably 
more frequently belong to the latter. 

In a word, the clays carrying plant remains are regarded as lagoon 
deposits made in ponded stream-channels and gradually buried be- 
neath the advancing beach of the Talbot sea. The clays carrying 
marine and brackish-water organisms are believed to have been at 
first off-shore deposits made in moderately deep water and later 
brackish-water deposits made behind a barrier-beach and gradually 



1>>>> THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

buried by the advance of that beach toward the land. Taking up the 
first class of deposits in more detail they are believed to have been 
formed in the following manner: 

During the erosion interval which immediately preceded the depo- 
sition of the Talbot formation many streams cut moderately deep 
channels in the land-surface which on the sinking of the region again 
were transformed into estuaries (Fig. 8). Across the mouths of the 



Fig. 9. Diagram showing advancing Talbot shore-line and ponded stream. 

smaller of these drowned valleys the shore currents of the Talbot sea 
rapidly built bars and beaches which ponded the waters behind them 
and transformed them from brackish-water estuaries to fresh-water la- 
goons. These lagoons, however, were gradually changed into marshes 
and possibly to meadows by the inflow of detritus from the surround- 
ing region and on the new land-surface thus formed various kinds of 
vegetation took up their abode (Fig. 9). At first the beach-sands ad- 
vanced in the lagoon and filled up completely that portion of the sub- 
merged trough which lay immediately beneath them, but later, as the 



MARYLAND GEOLOGICAL SURVEY 



189 



lagoon was silted up more and more with mud derived from the sur- 
rounding basin, the advancing beach came to rest on this lagoon de- 
posit as a foundation and arrived at length at the point where the 
lagoon had been filled up to the level of wave-base or higher. When 
this place was reached another process was added to that of beach ad- 
vance. Heretofore the waA^es and wind had been simply pushing for- 
ward material over the advancing front but now that the mud deposit 




Fig. 10. Diagram showing later stage in advance of Talbot shore-line. 

in the lagoon had actually reached the level of wave-work and had 
transformed the lagoon from a pond to a marsh or to a meadow, the 
breakers attacked the upper portion of the lagoon deposit and eroded 
it down to the level of wave-base as rapidly as they could reach it from 
under the superficial veneer of the beach-sands. Cypress, cat-tails, 
sedges, and other vegetation which had taken up their abode in the 
marsh would be overwhelmed with detritus by the advancing beach 
and a little later be destroyed by the breakers. In this way all traces 
of life must be removed from the deposit except such as happened 



190 



THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 



to occupy a position lower than wave-base. One therefore, finds pre- 
served in the clay water-logged trunks and leaves, nuts, etc., and roots 
of huge trees like the cypress which would tend to sink by their 
great weight further and further into the soft mud as the trees in- 
creased in size. The area over which the waves had removed the 
upper portions of the lagoon deposit can be determined not only by 
the presence of truncated stumps but also by the character of the 
contact. Here there is a sharp division between the clay and the 
overlying sand and gravel while the. area over which the beach ad- 
vanced without cutting would be indicated by a partial mingling of 
the beach material with lagoon mud. 

A still later stage in the process is illustrated in the accompanying 
diagram (Fig. 10) which represents a stage where the waves have so 

B CD 




Fig. 11. Ideal section showing advance of Talbot shore-line. 

far advanced as to largely destroy the original stream channel. A small 
portion of the old lagoon still exists at the head of the swamp but its 
lower portions have long since been submerged and covered over by 
the advancing beach. The transverse section shows what is left of 
the lagoon deposits of mud carrying truncated stumps of cypress and 
other trees which happened to be buried deep enough to escape the 
destructive powers of the breakers. The broken line indicates the 
outline of the clay lens. Fig. 11 is a section through the same region 
made at right angles to the one just described. At D the breakers 
arc forcing forward the beach upon the meadow. Just off from the 
bcacli the waves have swept away the sand and are eroding on the 
lagoon mud which reached out in them under the beach veneer. At 
C the waves have succeeded in cutting down the lagoon deposit to 
wave-base and have left behind a thin veneer of sand and erravel as 



MARYLAND GEOLOGICAL SURVEY 191 

the sinking land carries it below the reach of the waves. At B the 
lagoon deposit was not thick enough to reach the zone of wave-ero- 
sion and simply grades up into a thick deposit of sand and loam which 
passes out toward A. 

The second category of clay lenses, namely those carrying marine 
and brackish-water organisms are understood to have been formed 
in a somewhat different manner. The lower portion carrying the 
marine organisms points to salt-water conditions and contains remains 
of sea animals which live to-day along the Atlantic coast. At the 
time when this deposit was formed, the ocean waters had free 
access to the region and the blue mud in which they are now imbed- 
ded and in which they lived was a quiet-water deposit laid down some 
distance from the land. Later, however, it would appear that a 
barrier beach was constructed shutting off a portion of the sea-bed 
which had formerly been occupied by marine animals and gradually 
allowing it to be transformed from salt-water conditions to those of 
brackish water. In this brackish-water lagoon the fauna changed to 
that found along our estuaries to-day and huge oysters flourished and 
left behind them a deposit of shell-rock. "With the bar advancing 
landward this lagoon was gradually filled up with sand and gravel 
and finally obliterated. 

The upper unconformity, then, in the case of the fresh-water and 
the brackish-water lagoons is real only in the sense that an uncon- 
formity in a cross-bedded wave- and delta-deposit is real. There is, 
it is true, a lack of harmony in the position of the beds and a. sharp 
break is indicated but there is no indication of an appreciable time- 
lapse between the clay and the oyster-bed on the one hand and the 
overlying sands and gravel on the other, and the sea which eroded the 
clay to a fixed level immediately afterwards overspread the surface of 
the same with a veneer of beach sand. There is, therefore, no time 
break indicated by this unconformity and the lenses of swamp-clay 
as well as those carrying marine and brackish-water organisms are to 
be looked upon not as records of elevation and subaerial erosion but 
as entombed lagoon-deposits made in an advancing sea and contempo- 
raneous with the other portions of the formation in whose body they 
are found. 



192 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

The hypothesis here advanced is based on and reinforced by many 
observations along the present shores of the Atlantic Ocean, Chesa- 
peake Bay, and its estuaries. Each step in the process described 
above is there illustrated and some of them are met with again and 
again. 

As one passes along the shores of Chesapeake Bay and of the rivers 
which flow into it, stream channels are continually met which have 
arrived at more or less advanced stages in the above mentioned pro- 
cess. Some are in part converted into lagoons, by bars built across 
their mouths, others show partial filling by mud washed in from the 
surrounding country, and still others have reached the advanced 
stage of swamps or meadows in which various types of vegetation are 
flourishing. In Virginia, in addition to the usual undergrowth which 
is found in wet places, the cypress has taken up its abode in these 
lings and has converted some of them into cypress swamps. For 
great stretches along the shore the advance of the sea is indicated 
by well-washed cliffs while in other places the waves are found de- 
vouring beds of clay which are situated immediately in front of la- 
goon swamps and separated therefrom by nothing but a low super- 
ficial beach. These clay beds invariably lie at and below water-level, 
are very young in age and evidently pass directly under the beach to 
connect with the lagoon-clay beyond. This interpretation is made 
the more certain by the presence of roots in the wave-swept clays 
which but a short time before belonged to living plants identical with 
those now flourishing behind the beach, and point to a time not far 
distant when they also were a part of the lagoon swamp behind a 
beach situated a little farther seaward. At Chesapeake Beach 
a ditch has been cut through one of these beaches which shows a con- 
tinuous deposit of clay from a lagoon swamp passing out under the 
beach to the Bay beyond. The waves are thus caught, as it were, in 
the act of eroding the upper portion of the lagoon deposit. 

From a large body of data gained from over a wide area, it is evi- 
dent that the erosion which occurred during the interval between 
the elevation of the Talbot terrace and the present subsidence of the 
coast was sufficient to permit streams to cut moderately deep valleys 



MARYLAND GEOLOGICAL SURVEY 193 

m the former. It would then appear that as the region was gradually 
lowered again beneath the present ocean the upper portions of the 
stream-channel in time passed below wave-base and whatever has col- 
lected in them since that period will be preserved beneath the ad- 
vancing sea as a more or less fossiliferous clay lens apparently un- 
conformable beneath beach debris. 

The barrier beaches which exist at intervals along the Atlantic 
coast of New Jersey, Delaware, Maryland, Virginia, and southward 
show us how portions of the ocean-bed, which were formerly bathed 
by salt water and sustained a marine fauna, are now converted to 
lagoons behind barrier beaches, and have passed over in varying 
degrees to brackish-water conditions bearing estuarine faunas. 

Similar deposits to those just described have been seen by the 
author along the Rappahannock river, especially at Mosquito Point, 
and there is no reason to doubt that they occur in many other places 
along Chesapeake Bay and its estuaries, within the State of Virginia. 
From analogy, it would be expected that similar deposits should be 
discovered along Delaware Bay where conditions must have been 
identical to those which prevailed in Chesapeake Bay. That such 
deposits do occur along the shores of the Delaware there can be no 
doubt. The most noted of these is at Fish House on the New Jersey 
side of the Delaware river a few miles above Philadelphia. 

The drab clays at Fish House, New Jersey, which have occasioned 
a large amount of discussion and have given rise to a somewhat volumi- 
nous literature, have been variously assigned to deposits ranging all 
the way from Cretaceous to post- Wicomico. Mr. Lewis Woolman 
has very admirably summed up the literature regarding this forma- 
tion as well as all the evidence which is at hand. 1 It is clear from 
the facts which he brings forward that the Fish House clays are ex- 
tremely late in geologic history. Mr. Woolman inclines to assign 
them to the Pensauken of Professor R. D. Salisbury, in this respect 
following Professor Salisbury's last utterance on this point. It ap- 
pears that the reason for assigning the Fish House clay beds to 

' Annual Report State Geologist of New Jersey, 1896 
13 



194 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 

" Pensauken " is on account of a thin bed of gravel carrying Triassic 
shale cobbles and having the general aspect of " Pensanken." Pro- 
fessor Salisbury on this ground concluded at first that the Fish House 
clays were " post-Pensauken " but in the subsequent year assigned 
them to the " Pensauken " formation. 1 Mr. \Voolman on account of 
the presence of Newark shale above the clay regarded it as lying in 
the body of the so-called Pensauken formation. 

The author regards the Fish House clays as identical in age and 
manner of formation with similar deposits further south, and conse- 
quently refers them to the Talbot formation. 

1 Annual Report State Geologist of New Jersey for 1895, p. 8. 



THE MINERAL RESOURCES OF CECIL 

COUNTY 

BY 

EDWARD BENNETT MATHEWS 



Introductory. 



The mineral resources of Cecil county are not as important sources 
of wealth to the people of the area as the rich farm lands, although 
the variety of mineral products which are worked for their intrinsic 
value is great. The distribution of these products is widespread 
throughout the northern and central parts of the county and the 
benefits are accordingly not confined to any single neighborhood. 
The materials which have been proved to be of value to the people 
of the county are building-stone, road-metal, iron ore, clays, kaolin, 
flint, feldspar and chrome. Some of these, however, are not at pres- 
ent worked owing to the condition of the market and the finding of 
deposits in other regions which can supply the trade at lower prices 
than those at which it is possible to produce the same material in 
Cecil county. 

The most prominent sources of mineral wealth in the county are 
to be found along the various lines of communication either by rail- 
road or by waterway; thus the most important operations in building 
stone are at Port Deposit, while the clays and kaolin are worked 
most extensively along the lines of the Baltimore and Ohio and Penn- 
sylvania railroads. This, however, does not mean that there are 
not deposits of equal extent and quality in other portions of the county 
as will be shown in the following pages. The presence of mineral 
deposits is often unrecognized by the inhabitants owing to the fact 
that in the uplands lying to the north of the railroads they are 
covered by a rich soil whose fertility fully compensates for any loss 



196 THE MINERAL RESOURCES OF CECIL COUNTY 

which may have arisen through ignorance of their presence beneath 
the surface. 

Building-stoke. 

The building-stone quarries at Port Deposit, Frenchtown, and less 
important areas in the county are yielding a large share of the in- 
come derived from working the mineral resources of the county and 
probably no industry is on a firmer footing in the community than 
that of quarrying building- and crushed stone. The stone which 
is here quarried is placed on the market as a granite although scien- 
tifically, as described in the preceding paper on the crystalline rocks 
of the county, it is grouped in the recently established class of igneous 
rocks, known as monzonites. 

PORT DEPOSIT. 

The largest and most successfully operated quarries within the 
county are situated at Port Deposit where they support the main in- 
dustry of the town. The rock at this point as shown in the accom- 
panying photograph is admirably situated for quarrying and shipping 
purposes. By the railroad which passes by the quarry there are good 
connections with Philadelphia, sixty-seven miles distant, Baltimore 
forty-three, Washington eighty-three and Harrisburg, sixty-five miles. 
From the wharf nearby may be loaded light-draft vessels which can 
carry the material without transhipment to Philadelphia, Baltimore, 
Washington, and Richmond at very low freight rates. The rock-wall 
rising directly from the level of the water to a height of 200 feet 
above sea-level offers exceptionally fine facilities for the quarrying 
of granite without the serious difficulties arising from water and 
the removal of worthless material, so often encountered in quarries 
which are sunk below the surface of the surrounding region. 

The value of the granites and the opportunities offered for quarry- 
ing were early recognized and the rock was used by the settlers for 
the foundations of some of the old colonial dwellings in the region. 
The industry arising from the quarrying of the rock is, however, of 
somewhat later origin. 

In the years 1816-1817 a bridge was built across the Susquehanna 



MARYLAND GEOLOGICAL SURVEY 



CECIL COUNTY, PLATE XVII. 




FtG. 1.— VIEW SHOWING LOCATION OF McCLENAHAN GRANITE QUARRY, PORT DEPOSIT. 




FIG. 2 — KAOLIN-WASHING PLANT, MARYLAND CLAY COMPANY, NORTHEAST 



MARYLAND GEOLOGICAL SUKVEY 197 

river at Port Deposit by the Port Deposit Bridge Company. During 
the process of construction the abutments for the eastern approach 
were made from stone quarried at the eastern end of the bridge, 
which is within the present corporate limits of the town of Port 
Deposit and not far from the site of the McClenahan quarries. For 
about ten years the opening so made was worked in a small way by 
Mr. Simon Freeze, who had supplied the materials used in the con- 
struction of the bridge. In 1829 the owners of the Maryland canal 
became interested in the quarry, and increased its workings. In 
1830 the business passed into the hands of Messrs. Samuel Megredy 
and Cornelius Smith, who still further increased the scope and opera- 
tions, and developed a considerable trade with Baltimore and other 
coastwise towns. Two years later Mr. Ebenezer D. McClenahan 
became interested in the granite quarrying industry through his 
brother-in-law Mr. Daniel Megredy, who w T as then a successful opera- 
tor. McClenahan became the dominant factor in the local devel- 
opment and gradually increased the business until in 1837, from 
data furnished by Anthony Smith, Ducatel l estimated the annual 
output at from 12,000 to 15,000 perches. On the retirement of Mr. 
E. D. McClenahan the business was transferred to his sons, who are 
at present the principal owners in the Port Deposit company. 

The quarries at Port Deposit are in rocks of igneous origin, which 
have been variously modified by severe dynamic action. This has 
produced a certain degree of schistosity which causes the Port Deposit 
granites to be taken at times for gneiss rather than granite. This 
foliation which is produced by the parallel arrangement of the black 
mica flakes has a northeasterly trend nearly at right angles to the 
course of the river and a dip that is almost vertical. There is no 
marked banding in the rock, but the whole face of the quarry, which 
shows thousands of feet of surface, appears perfectly homogeneous, 
as though made up of a single rock. Through this mass there now 
pass several series of intersecting joints of which the most prominent 
approximately coincides with the northeast trend of the foliation, but 
which inclines somewhat to the dip of the foliation. A second set 

[ Ann. Rept. of the State Geologist of Maryland, 1S37, p. 15. 



19S THE MINERAL RESOURCES OF CECIL COUNTY 

of joints runs almost at right angles to the first and is almost as sharp 
as those of the main series. A third set trending west of north is 
inclined 60° to the principal joints, while a fourth set, approximately 
horizontal, serves as bedding joints. The surface of the jointing- 
plane is usually quite smooth and even, but the direction and distance 
between the parallel surfaces is not always constant. This produces 
a slight wedging in the blocks, which increases somewhat the cost of 
quarrying. On the other hand the smoothness of the joint surface 
frequently renders the rock ready for use in building without the 
intervention of the stone cutter, and allows the extraction of enor- 
mous nearly rectangular blocks. The expenses of preparing the rock 
for use in the wall is accordingly reduced. 

Although there are some half dozen series of jointing the rock a 
short distance below the surface is very compact, homogeneous, and 
strong, as is shown by the pressure tests of Gillmore, who found that 
the compressive strength of this rock was 13,100 pounds per square 
inch when tested " on edge," and still more clearly by the more re- 
cent tests 1 which show a crushing strength of over 80,000 pounds on 
two inch cubes. The incipient jointing planes, although so closely 
welded together as to show this great strength, are made use of by 
the quarrymen in trimming the huge monoliths and in cutting the 
smaller Belgian paving blocks, as the rock may be readily opened by 
means of wedge and " feathers." 

The distance between the major joints, which varies from half an 
inch to several feet, is sufficiently great to allow the extraction of 
any sized block, which can be handled advantageously by the ma- 
chinery and by the transporting agencies. It is usually considered 
that the rock of the Port Deposit quarries is somewhat more easily 
worked than that at Frenchtown, which is otherwise indistinguish- 
able. This difference in working arises in part no doubt from the 
greater age of the quarries, better facilities for quarrying and hand- 
ling, and also from the more convenient position of dominant lines of 
working in the Port Deposit quarries. 

The texture of the Port Deposit granite, or granite-gneiss is highly 
characteristic. The rock is composed of the usual granitic constitu- 

1 Edward B. Mathews, Maryland Building Stones, Md. Geol. Survey, vol. ii, L898, 
pp. 144-145. 



MARYLAND GEOLOGICAL SURVEY 199 

ents, quartz, potassium and soda-lime feldspars, biotite and accessory 
minerals. The most noticeable feature of the rock is the secondary 
gneissic structure, which is brought out by the arrangement of the 
shreds and flakes of black mica. This arrangement, which is better 
shown in the ledge and the hand specimen than in a thin section, is 
seen on examination to be due to small disconnected groups of mica 
flakes, which lie in approximately parallel lines. These lines are 
not straight or continuous, but are wavy and the flakes are dissemi- 
nated or overlapping in such a way as to produce the well-known len- 
ticular effect of gneiss. The texture differs from that of true 
gneisses, however, in showing no banding due to changes in the com- 
position or coarseness of grain of the rock. 

The color of the rock is a light bluish-gray, which in buildings 
gives a bright fresh appearance at first and then gradually becomes 
somewhat darker through an accumulation of the dust and dirt in 
the atmosphere. Such a darkening of the rock produces a mellowed 
pleasing effect in structures situated in most of the cities. The 
roughness of the surface, however, and the abundance of the black 
mica render the appearance of the older buildings constructed from 
this rock somewhat sombre, if the atmosphere is strongly charged 
with dust particles. This is particularly true in cities where soft 
coal is extensively used without smoke consumers. On the whole 
the appearance of this rock is unusually pleasing. 

The chemical composition of the Port Deposit granite is shown in 

the following analysis of a specimen from the McClenahan quarry 

made by the late Dr. Win. Bromwell. Strictly speaking the rock 

would seem to be a quartz monzonite rather than a true granite since 

the relative amounts of potash and soda for the feldspars indicate a 

relative lack of the potassium feldspar. 

Analysis of Pout Deposit Granite. 

Si0 2 73 . 69 

A1 2 3 12.89 

Fe 2 3 1 . 02 

FeO 2.58 

CaO 3 . 74 

MgO 50 

Na.,0 2.81 

K 2 6 1 . 48 

H 2 1.06 

Total 99.77 



200 THE MINERAL RESOURCES OF CECIL COUNTY 

According to the recalculations of Miss Bascom given in her dis- 
cussion of the Crystalline Rocks of the county, the average mineral- 
ogical composition of the rock disregarding the secondary constit- 
uents is as follows: 

Quartz 42 .28 

Orthoclase 8.91 

Oligoclase 34 . 86 

Biotite 10.41 

Misc 3.16 

Total 99.62 

A microscopic study 1 of sections from the Port Deposit granite 
shows the presence of the usual granitic minerals, such as quartz, 
feldspar, dark and light micas, apatite, zircon, titanite, allanite, epi- 
dote, chlorite, hornblende, magnetite, garnets and occasionally calcite. 
The quartz is in relatively large sized areas, ranging from 0.5 mm. 
x 1.5 mm. to 3 mm. x5 mm. With the aid of the microscope these 
areas are seen to be not single units, but composed of a great number 
of small quartz fragments, which have resulted from the crushing 
and recrystallization of the original granite during the period when 
the rock received its present schistose structure. These smaller 
quartz fragments are aggregated together by intricate interlocking 
sutures in a way which renders the rock less rigid and at the same 
time capable of withstanding fully as much pressure as an individual 
grain. The interstitial areas between the fragments of the coarser 
mosaic are filled with a mosaic of still smaller grains. The feldspars, 
like the quartz, occupy well defined areas and show the shattering 
and recrystallization into a mosaic, as a result of the dynamic forces 
which have modified the rock. These mosaics are much less frequent 
in the feldspars than in the quartz. The biotite occurs in aggregates 
of fine shreds, showing varying degrees of orientation, and is fre- 
quently associated with irregular grains or small crystals of epidote, 
titanite and allanite. The shreds and flakes are so small and so inter- 
locked with minute grains of quartz, that they cause little decrease 
in strength because of schistosity. The other constituents are so insig- 

1 For a further discussion see ante pp. 117-119. 



MARYLAND GEOLOGICAL SURVEY 201 

nificant in quantity and so stable under atmospheric conditions that 
they do not influence appreciably the physical or chemical stability of 
the rock. 

In any discussion or consideration of building stones, in order to 
appreciate the practicability of the rocks for large and permanent 
structures, it is necessary to know something of their physical proper- 
ties. Among these the most important are specific gravity, the ratio 
of absorption, the effect of freezing and thawing, and the compression 
strength. The specific gravity must be known in order to compute 
the weight to each cubic foot of the rock, which in turn indicates the 
amount of pressure imposed on the lower courses of the structure. 
Since almost all building stones are exposed to the atmospheric agents 
which influence them, it is well to know also what effect the varying 
conditions of temperature have upon a given stone. For example 
heating, due to the rays of the sun, causes the minerals to expand. 
Since the rate of such expansion is different for different minerals and 
even for different directions in the same mineral, there is unequal en- 
largement of the grains, and hence a loss in the cohesive strength of 
the rock. Other things being equal this change is greater in aggre- 
gates composed of many and vari-colored constituents. Again, if the 
rock is porous, the expansion of included moisture may rend the rock 
m freezing weather, thus it becomes necessary to know the amount 
of moisture absorbed by the rock, and so liable to expansion through 
frost action. The values obtained by Gillmore 1 on Port Deposit 
granite are as follows: 

Weight Ratio 
Strength Strength of 1 of 

_ ... , of per cubic absorp- 

Fosition. Cracked, spec. sq. in. Sp. gr. ft. tion. Remarks. 

On bed 79,000 19,750 2.720 170 Coarse, strongly dashed with black. 

On edge, 33,000 52,400 13,100 2.720 170 do 

On bed 66,000 16,500 2.720 170 do 

" " 60,000 15,000 2.720 170 Burst suddenly. 

In the tests made during the search for a stone suitable to be used 
in the building of the Smithsonian Institution at "Washington several 

1 Gillmore, Reports on the Compressive Strength, Specific Gravity and Ratio of 
Absorption of the Building Stones in the United States. Rept. of the Chief of 
Engineers for 1875, Appendix II, p. 847. Also Republished Svo. 37 pp. Van Nost- 
rand, New York, 1S76. 



202 THE MINERAL RESOURCES OF CECIL COUNTY 

.Maryland building stones were studied, among which was included 
the Port Deposit granite. Dr. Chas. G. Page, in his report on the 
action of frost on certain materials for building, gives as the specific 
gravity for the Port Deposit the figures 2.609, and as the loss by frost 
in grains 5.05. The method of investigation was the so-called Brard 
process, which consists in substituting the crystallization of sulphate 
of soda for the freezing of water. 

The tests published in the second volume of the Maryland Geo- 
logical Survey Reports are even more creditable to the rock. The 
specimens submitted were two inch cubes, carefully prepared and 
subjected to tests under the most uniform conditions. The results 
are as follows: 

Simple Crushing. Absorption, Freezing, Crushing after freezing. 

, ■ , percentage percentage ' 

Crack. Break. of gain. of loss. Crack. Break. 

67,100 0.253 0.000 83,000 sr.,000 

79,200 0.193- 0.011 78,100 90,800 

86,200 

101,540 

Tests made by Messrs. Booth, Garrett, and Blair, of Philadelphia, 
on a 2-inch cube gave the crushing strength as 84,730 pounds for 
2-inch cubes. 1 

The results of these various investigations clearly show that the 
Port Deposit rock is strong enough to withstand all the demands made 
upon it by the pressure of superimposed stone work in structures, 
and to resist the various deteriorating influences of frost and atmos- 
phere. 

This view of the durability of the Port Deposit granite is well sus- 
tained by a study of its mineralogical and chemical composition, and 
the evidence of disintegration shown in the quarries and in old struc- 
tures. The mineralogical composition indicates stability, as no min- 
eral is present more liable to alteration than the oligoclase feldspar, 
which itself is not particularly prone to decomposition, although the 
first of the prominent constituents to yield to atmospheric action. In- 
vestigation at the quarries, where a considerable depth of decomposed 
rock is seen to overlie the more marketable material suggests the sus- 

•18th Ann. Rept. U. S. Geol. Surv., pt. V, 1*97, p. 904. 



MARYLAND GEOLOGICAL SURVEY 203 

picion, that the Port Deposit granite will not withstand atmospheric 
agencies for any great period of time. . This deceptive appearance 
arises from the fact that the crystalline rocks southward from Phila- 
delphia have not been scoured and cleaned by the action of glacial 
ice as in more northern latitudes. Thus the overlying waste repre- 
sents the decomposed products of several geological epochs. 

The number of quarries about Port Deposit has never been very 
large, although now and then attempts have been made to establish 
rivals to the large quarries which are at present operated by the 
McClenahan Granite Company. 

FRENCHTOWN. 

At the eastern end of the high suspension bridge of the Baltimore 
and Ohio railroad over the Susquehanna river there is a small quarry 
opened in a schistose granite, which is very similar to that worked 
at Port Deposit. This quarry was probably first opened during the 
construction of the railroad bridge, 1 but nothing of economic import- 
ance was done here until the firm of AVm. Gray and Sons of Phila- 
delphia became interested in 1894. At this time the capital invested 
was about $S,000, a sum which represents but part of the present 
investments. ISTo work of any particular moment was done by the 
present owners until the autumn of 1896, when the receipt of some 
moderate sized contracts encouraged the further opening of the 
quarry, which now bids fair to establish a well organized industry at 
Frenchtown. The only buildings of importance which have been 
built from the Frenchtown rock are the Cold Storage Warehouse and 
an extension of the Baldwin Locomotive Works in Philadelphia. 

The location of the quarry topographically and geologically is simi- 
lar to that of the quarries at Port Deposit. The ground is stripped 
upon the side of a hill and the quarry has worked down to the level 
of the low bench, along which runs the Port Deposit and Columbia 
Railroad. The jointing of the rock is similar to that at Port Deposit, 
and there are here three prominent sets of joints intersecting approxi- 
mately at right angles. Members of the same series are so placed 

1 The main piers of the bridge are built of Port Deposit granite. 



204 THE MINERAL RESOURCES OF CECIL COUNTY 

as to facilitate working of the quarries and blocks containing 3,000 
to 4,000 cubic feet might easily be obtained. 

The texture of the rock, like that at Port Deposit, is coarsely gran- 
ular, with a secondary lamination, and is adapted to all ordinary uses 
in general building, exterior ornamentation, curbing, paving, etc. It 
is possible, however, that this rock may be a little more " plucky " 
in working than the larger deposit farther north. Like the rock 
quarried at Port Deposit, that at Frenchtown frequently appears 
somewhat disfigured by small black patches or basic segregations of 
biotite, which often render the stone unavailable for the highest 
grades of ornamental work. The microscopical characteristics of this 
rock as well as the color and texture are the same as those of the 
Port Deposit rock already described. The quarries have not been 
worked long enough to indicate by the product the durability of the 
rock or to call for discussions of its specific gravity, crushing strength 
and other physical features. There is no doubt, however, that the 
rock will respond readily to all the demands made upon it for ordi- 
nary building purposes, and that it will resist any pressure or atmos- 
pheric influences which it would normally encounter. It weighs 
about 170 pounds to the cubic foot. 

The quarry as yet is small. The transportation facilities, however, 
are very good, the same as those at Port Deposit. The stone may be 
loaded directly on the cars for Philadelphia and Baltimore or on 
barges for these and other coastwise points. 

Clay. 1 
Second only in importance to the building-stone industry is that 
supported by the deposits of sands, kaolins and clays found within 
the limits of Cecil county. Clays suitable for the manufacture of 
brick or higher grade materials are found in almost every part of 
the county but are particularly well developed and well situated for 
use in the area along the Pennsylvania and Baltimore and Ohio 

'Based on II. Ries, Clays of Maryland, Md. Geol. Survey, volume iv, Baltimore, 
L902. In this report is a complete discussion of the properties of clays, the methods 
of Working and the distribution and character of Maryland clays. 



MARYLAND GEOLOGICAL SURVEY 




Patuxent 



LZ 

MAP OF CE 
SHOWING AREAL DISTRIBUTION OP CLA' 



CECIL COUNTY, PLATE XVIII 




Geolog y by Arthur Bibbins tsa-o 



_J Patapsco ' I 

?RAL CECIL COUNTY 

BEARING FORMATIONS OF THE POTOMAC GROUP 

ale 62500 



Raritan 



MARYLAND GEOLOGICAL SURVEY 205 

railroads and along the shores of the Northeast and Elk rivers. To 
the north of this area most of the clays found are of residual origin, 
that is, they have been formed by the disintegration of the under- 
lying rocks until the remaining particles forming the soil are so fine 
that they move over each other readily when mixed with the proper 
amount of water. Because of the abundance of higher grade clays 
elsewhere in the county these residual clays have not been worked 
to any considerable extent except for kaolin. 

The area supporting the most active operations in the manufacture 
of clay products at the present time is found along either side of the 
Pennsylvania Railroad from Perryville eastward to the Delaware line. 
On either side of this railroad are deposits of clay, some of which are 
suitable for high grade refractory goods, some for ordinary stoneware 
or terra cotta, and some only for common brick. 

The gradual increase in depth below the surface of the valuable 
clay beds in passing diagonally across the county from northwest to 
southeast causes them to be too deeply buried beneath the overlying 
sands and gravels for profitable working in the southern part of the 
county except along the waterways. Thus there are no clay pits or 
clay-working establishments found in the Chesapeake and Cecilton 
election districts. 

The clays of Elk Neck and the land bordering the estuaries be- 
tween Northeast river and Perryville may be classified roughly into 
three main types, those which are suitable for brick and tile and 
terra cotta; those suitable for stoneware; and those for refractory 
purposes, such as stove-linings, fire-brick, or saggers. Besides these 
three uses there are occasional deposits of sufficient purity and bril- 
liancy of color to make them useful in the manufacture of paints. 

The following discussion of the clay resources of Cecil county will 
treat in succession the character and distribution of the clays best 
suited to the manufacture of brick and terra cotta, stoneware, and 
refractory goods. The deposits under each topic will be grouped 
according to their relation to transportation facilities by railroad or 
waterway. 



206 THE MINERAL RESOURCES OF CECIL COUNTY 

BRICK AND TERRA COTTA CLAYS. 

The brick and terra cotta clays of the area along the railroad are 
best developed in the areas about Perry ville, Principio, Charlestown, 
Bacon Hill, and Elkton. 

In the railroad cut just north of Perryville station is an exposure 
of Pleistocene clay suitable for brick manufacture at least 12 feet 
thick and 600 feet long. The location of this bed so near the track 
increases its value because of the ease with which either the raw 
clay or the finished product may be shipped. At the deep cut east 
of Principio station there is an unusually large bed of variegated 
clay of Patapsco age which is likewise very well situated for ship- 
ping facilities. The clay at this point is at least 20 feet thick and is 
overlain by 15 to 25 feet of merchantable sand. The clay is the 
ordinary red and white variegated clay, which is rather dense 
and tough requiring more pugging that is usually given to thor- 
oughly mix the red and white streaks to a uniform color. An- 
other large body occurs in the hill west of Charlestown where 
the large amount of clay and the situation near railroad and tide- 
water means of transportation make an ideal site for a brick-making 
plant. At this place and nearby at Broad Creek there are other clays 
suitable for the manufacture of stoneware and pottery. Still another 
favorable site for an extensive clay-working establishment occurs in 
the immediate vicinity of Bacon Hill station where there are prac- 
tically inexhaustible supplies of variegated Patapsco clays suitable 
for the manufacture of brick or possibly terra cotta. The local brick 
plant at Elkton uses Pleistocene clay. The new railroad cut east of 
Elkton near Grays Hill exposes other large deposits of immense 
extent of variegated and drab clays. This would seem to be an ex- 
cellent location for the development of an extensive brick-making 
plant with its excellent railroad connection with Philadelphia. Wil- 
mington and Baltimore. 

The brick deposits on the shores of Elk Neck are less valuable 
than those already mentioned but their excellent location for the 
transportation, by water, of the raw product or of the manufactured 



MARYLAND GEOLOGICAL SURVEY 207 

articles, together with their fine exposure in the cuts made by the 
Bay render them possible sites for brick-yards and clay-working estab- 
lishments. The more valuable clays are situated a short distance 
from the shore-line but within easy haul of landings. Samples of 
the chocolate-colored clay exposed in the embankments along the 
highway 3£ miles south of ISTortheast on the way to Elk Neck show a 
very fair plasticity. The degree of fineness can be estimated roughly 
from the fact that more than 90 per cent of the material passed 
through a sieve of 150 meshes to the inch. Tests made from the 
samples showed the clay to possess the following properties: It re- 
quired 20 per cent of water to mix it to proper plasticity and the 
bricklets made had an air-shrinkage of 5 per cent and an average 
tensile strength of 100 pounds per square inch. At cone 5, which is 
about the temperature reached in some common brick kilns, the clay 
burned to a buif color but could still be scratched with, a knife. 1 
Other exposures of brick-clay occur on the old " Neck Road " about 
three miles south of Elkton and just north of Plum Creek; in 
Thompson's gulley, where there is an exposure of a bed of at least 
20 feet thick; and about two and a half miles south of Northeast on 
the shores of Northeast River. 

In the areas to the southeast of Elk Neck and northward from the 
Baltimore and Ohio Railroad there are at present no plants manu- 
facturing brick or terra cotta. There is, however, an idle plant at 
Welsh Point which was erected for the grinding, cleaning and drying 
of clay for shipment. The clay used occurs in two beds, namely, 
an upper and a lower blue, the latter lying for the most part below 
tide-level. 

STONEWARE CLAYS. 

The localities for stoneware clay along the railroad are almost the 
same as those enumerated for brick- and terra cotta clay. The best 
clays for this purpose come from near the base of the Patapsco for- 
mation but there is often a deposit of bluish-gray plastic clay lying 
just beneath the variegated clays. 

1 Additional details may be gained by reference to the Report on the Clays of 
Maryland, by Heinricb Ries. 



208 THE MINERAL RESOURCES OF CECIL COUNT Y 

A good example of this lower bluish clay is seen in the property 
of Mi - . Warren Grosh, on the Bacon Hill road about 3^ miles east 
of the town of Northeast. The material is a blue plastic clay known 
to be from 7 to 10 feet thick which lies below the level of the wagon 
road. "With it there occurs some yellowish clay forming about one- 
third of the whole mass. This is dug and shipped with the blue 
material. The clay is sent to stoneware factories in Philadelphia. 
A physical examination made by Professor Pies showed that 
tempering this clay required 23 per cent of water and that the brick- 
lets from it had an average shrinkage of 6 per cent. The average 
tensile strength of the air-dried briquettes was found to be 111 pounds 
per square inch. In burning incipient fusion occurred at cone 01 
with a total shrinkage of 9 per cent, the color of the burnt clay being- 
cream white. At cone 02 the shrinkage was 10 per cent, at cone 
4, 11 per cent, and at cone 5, 15 per cent. The clay was then nearly 
vitrified and vitrification actually occurred at cone 8, with a total 
shrinkage of 16 per cent. The chemical composition of this clay 
is shown in the following analysis: 

Analysis of Stoneware Clay, Bacon Hill, Cecil County. 

Silica 65.70 

Alumina ••••.... 20.30 

Ferric oxide 1.00 

Lime 3.50 

Magnesia 1 . 44 

Alkalies 02 

[gnition 7.60 

Total 100.10 

Total fluxes 6 . 56 

Another important clay deposit is found along the shore at the 
head of Beach Channel northwest of Carpenter Point on the prop- 
erty of Mr. J. F. Simpcoe. At this point the bed is fully 20 feet 
thick, but owing to the fact that it has not been worked extensively 
the clay deposit does not appear prominently at the surface. Tests 
were made upon this clay and the results may be summarized in the 
statement that it probably is a stoneware clay but not a fire-clay, and 



MARYLAND GEOLOGICAL SURVEY 209 

that it could be used in the manufacture of structural material if a 
buff color were desired. An analysis of this clay is given below: 

Analysis of Stoneware Clay, Carpenter Point, Cecil County. 

Silica 72.50 

Alumina 17 .00 

Ferric oxide 1 . 50 

Lime .35 

Magnesia .60 

Alkalies 1 .10 

Ignition (3.50 

Total 09 . 55 

Total fluxes 3.55 

A third deposit of importance occurs on the property of Mr. 
Charles Simpress about -| mile south of Eder. The exposures show 
three types of clay. The first, which is found at the bottom of the 
pit, is a fire-clay, which is sent to Cowden's brick works at Northeast 
for the manufacture of stove-brick. The second is a white fire-clay 
of good refractoriness which is mixed with the third and sent to R. 
Remey and Son, of Philadelphia, for the manufacture of stoneware. 
This third clay which contains considerable organic matter that 
passes off on burning is one of very fair refractoriness and would no 
doubt find application as an ingredient of a stoneware or terra cotta 
mixture. It could also be used in the manufacture of refractory 
wares. 

Stoneware clays occur at many places on Elk Neck and often are 
so situated as to facilitate shipment of the raw material or finished 
products by water. At Bull Mountain there is an important bed of 
dark plastic clay which forms a bluff 30 feet high with about 10 feet 
of overburden to the first bed. This clay slakes rather slowly, 
yielding a mass of very good plasticity and average tensile strength 
of 123 pounds per square inch when air-dried. It is perhaps better 
adapted to the manufacture of structural materials, terra cotta, or 
floor tiles than high-grade stoneware. At the northern base of Bull 
Mountain the stripping is as much as 30 or 40 feet, and here the 
working of the material would be unprofitable unless some use could 
be found for the overburden. Other stoneware clays are found near 

14 



210 TITE MINERAL RESOURCES OF CECIL COUNTY 

AVilson's Beach and about half a mile below the upper end of Maul- 
den Mountain. At this point there is a bed of blue potter's clay 
averaging 8 feet in thickness which outcrops at the water-level. Clay 
from this bank has been used to some extent by R. Remey and Son, 
of Philadelphia, in the manufacture of stoneware. The best stone- 
ware clay from the Elk Neck region, however, occurs on the prop- 
erty of Mr. Charles Simpress at a point about half-way between 
Hance Point and Roach Point. Just south of the termination of a 
private road the clay is exposed, showing an upper and a lower bed. 
The lower bed, with an average thickness of 8 feet, consists of a 
sandy clay containing mica scales. This slakes rather rapidly to a 
mass of moderate plasticity and an average tensile strength of 40 
pounds per square inch on the addition of 30 per cent of water. The 
clay, however, has a rather low shrinkage in burning a good refrac- 
toriness and a creamy-white color after burning, which would sug- 
gest that it might be a desirable ingredient for some pottery mix- 
tures. The upper bed is 4 feet in thickness and is composed of a 
buff fire-clay which burns white at low temperatures and light buff at 
higher temperatures. Material from these beds has been shipped to 
R. Remey and Son, of Philadelphia. 

No stoneware clays have been developed in the southern or north- 
ern areas, and it is quite possible that these districts are lacking in 
deposits which can be worked with profit. 

FIRE-CLAYS. 

Cecil county has numerous deposits of clay of sufficient refractori- 
ness to be classed as fire-clay, and these have been recognized and 
utilized for some time, especially at Northeast for the manufacture 
of stove-linings, front-brick, and other refractory goods. Most of 
the material which has been used as fire-clay has been found in the 
area lying adjacent to the Baltimore and Ohio and Philadelphia, 
Wilmington and Baltimore railroads. 

One of the clays used in making stove-linings at the factory of 
\\ r m. L. Cowden at Northeast is taken from the clay deposit on the 
property of Mr. Charles Simpress, situated one-half mile south of 



MARYLAND GEOLOGICAL SURVEY 211 

Ecler. The exposure at this point, as already described, consists of 
three types of clay, of which the red fire-clay is the lowest. The 
tests made by Professor Ries show the clay to slake comparatively 
slowly and to have a moderate air-shrinkage and low tensile strength 
with good fire-resistance. At a temperature of about 3,000 degrees 
the clay had not become viscous but still appeared vitrified. Plastic 
clay from the Thomas farm and a residual refractory clay from 
Gray's Perry, Pennsylvania, are also found in the mixture used by 
Mr. Cowden. The clays used by the Wakefield Pire Brick Com- 
pany are obtained from land either owned or leased by them. Sev- 
eral varieties are used and mixed in proportions suitable for the 
desired product. There are other good outcrops of fire-clay on the 
property of Mr. J. H. Ford near Northeast. While the exposure at 
this *point is not very large, the clay is similar to many of the same 
horizon which are exposed at other points, and its character is there- 
fore of interest. The tests made upon it show that it is fairly plastic 
and that it slakes rather slowly in water. At a temperature of 2,246 
degrees (cone 5) it burns white and is moderately hard. It does not 
vitrify, however, until heated to more than 3,000 degrees (cone 30) 
and consequently is a clay of excellent refractoriness. 

Fire-clays have been found on Elk Neck, but they have never 
been worked to any extent with the exception of the deposit at Hance 
Point already mentioned. Possibly the best occurrence of fire-clay 
in this area is that near MeKinneytown. This clay, however, must 
be hauled three miles to Northeast, or two miles and a half to North- 
east River. 

Kaolin. 

The kaolin deposits of Cecil county are a continuation of those 
of Delaware that have been so extensively drawn on in the manufac- 
ture of white ware. The material is really a residual clay derived 
from feldspathic gneisses comparatively free from minerals contain- 
ing iron. It is therefore white, or nearly so, and burns to a pure 
white after it has been washed free from any impurities. Up to the 
present time the kaolin industry of Cecil county has not proceeded 



212 THE MINERAL RESOURCES OF CECIL COUNTY 

beyond the prospecting stage except in the case of the Maryland Clay 
Company which has been engaged for some time in the actual mining 
and washing of the material. 

Kaolin has been located at many points within the county and the 
industry is likely to expand during the next few years. Owing to 
the presence of beds of sands, clays, and gravels of Patuxent and 
Columbia age, kaolin is rarely exposed at the surface and conse- 
quently is usually found either in making road or railroad cuttings or 
in the digging of wells. Where it is thus encountered or its presence 
suspected the extent of the deposit is further determined by test pits 
or borings. The amount of overburden above the kaolin varies from 
as little as two feet to as much as twenty feet in thickness. The depth 
of the kaolin itself is also quite variable and depends naturally on 
the depth to which weathering has decayed the parent rock, and also 
on the extent to which the deposit has been eroded by the currents 
which deposited the Patuxent sands. These sands are often of a refrac- 
tory character and are sold as fire sands. They represent the quartz 
and partially decayed feldspar particles which were present in the 
residual clays. The clay particles being very fine have either been 
floated off, or balled up into little plastic lumps from £ to 1 inch in 
diameter, which are found in the sands. 

Maryland Clay Company. — The following account of the kaolin 
deposits in Cecil county, together with the description of the one 
active plant in the area, is taken from the more exhaustive report on 
the clays of Maryland by Professor Hies. 1 

The Maryland Clay Company is the only one which is at present 
mining and washing clay. Its pits are located about 1 mile southwest 
of Northeast station, and between the highway and the Philadelphia, 
Wilmington and Baltimore Railroad. 

The kaolin is a decomposed feldspar mica gneiss overlain by Pa- 
tuxent sands on the western side of the pit and by Patuxent and 
Ploistocene deposits on the eastern side. 

These sands, which are often quite micaceous, vary in thickness 
from 10 to 40 feet, and have to be stripped off before the kaolin can 

1 Maryland Geological Survey, vol. iv, 1902, pp. 456-461. 



MARYLAND GEOLOGICAL SUKVEV 213 

be dug. The stripping is done with a steam-shovel. Between the 
kaolin and sand there is often a layer of sandy, micaceous clay, more 
or less mottled with limonite stains. This is sometimes sold for 
making saggers. 

The kaolin pit is a long opening running about northwest and 
southeast, with the washing plant near the latter end. 

Two grades of kaolin are recognized, the second having some iron 
stains. Both grades are washed, but the lower quality is sometimes 
sold in its crude form for fire-clay or sagger-clay. 

The method employed in washing the clay is not unlike that used 
at other works and consists in first dumping the crude kaolin and 
water on the sand-wheels. These, as is well known, remove 
much of the sand, and the remainder which remains in suspension 
together with the kaolin is washed along the troughing, where most 
of the fine sand is dropped before the settling tanks are reached. 
There are about 700 feet of troughing which is in 120-foot lengths. 
There are 3 settling tanks, from which the kaolin, after settling, is 
pumped into the filter press. Of these there are three, of Robinson 
make. 

The sand which is separated is thrown away. The kaolin is used 
chiefly for paper manufacture. 

The washed product forms 30^ of the quantity mined. 

The pressed clay is dried on racks in the open air. 

It is probable that with the development of the kaolin field in 
Cecil county additional washing plants will be erected. The works 
are shown in Plate XVII, Fig. 2. 

The washed clay from the pit of the Maryland Clay Company 
shows the following characteristics: There are considerable quanti- 
ties of small mica scales, whose presence is undoubtedly shown by 
the silica percentage found on analysis of the material as given below, 
still the material, which is used chiefly in the manufacture of paper, 
is very refractory, for there is not sufficient mica or undecomposed 
feldspar present to act as a powerful flux. As is the case with most 
kaolins the tensile strength of the material is very low and, therefore, 
no briquettes were made. Some bricklets of the material yielded the 



21-1- HUE MINERAL RESOURCES OF CECIL COUKTY 

following results: Air-shrinkage, \\$. When burned to cone 5 the 
total shrinkage was 9$, but the bricklel was still easily scratched, and 
had a very white color. At cone 10 the clay was barely scratched with 
a knife, and showed the total shrinkage 14$. The color was whitish. 
At cone 27, in the Deville furnace, the material had preserved its 
form perfectly, and showed signs of incipienl vitrification. In refrac- 
toriness it is fully equal to many of the best kaolins put on the market. 
Its composition is: 

Analysis of Washed Kaolin, NORTHEAST, Cecil Cotntt. 

Silica 55.65 

Alumina 30.53 

Ferric oxide -97 

Lime -75 

Magnesia -60 

Alkalies 30 

Moisture -35 

Water 12.30 

Total 100.35 

Total fluxes 2.52 

A sample of the second grade of crude kaolin from the Maryland 
Clay Company, at Northeast, was also tested. This differs from 
the first grade chiefly in having a larger percentage of iron oxide, 
and consequently the washed clay from it does not burn to as white 
a color. It is very sandy and when thrown into water falls apart 
very rapidly. 

A sample of the crude material was washed through screens with 
the following results: Residue on 80-mesh, 5.6#; on 100-mesh, 1.5$; 
on L50-mesh, 4.5#. 

The material therefore contains 88.4,'/ of grains sufficiently fine to 
pass a L50 mesh sieve. In actual practice, however, this is a much 
larger proportion than could be floated off to settle in the tank- em- 
ployed for that purpose. 

When burned to cone I the material -hows a total shrinkage of 5$ 
and is whin' in color, but above this it begins to develop a yellowish 
tint, so that it, could not. be used in the manufacture of good grades 

of white ware. 

It i- unaffected at cone 27 in the Deville furnace. 



MARYLAND GEOLOGICAL SURVEY 215 

Some good outcrops of kaolin are found in the cut of the Philadel- 
phia, Wilmington and Baltimore Railroad on the property of George 
W. Sutton at Perryville. This cut is the first large one on the road 
southwest of Jackson and at a point about one mile southwest of that 
station. There is, at this point, at least ten feet of the material 
exposed, but it has never been exploited to any great extent although 
a small quantity was shipped some time ago for trial. 

The material is covered by six to eight feet of Wicomico formation, 
but Mr. Sutton claims that in his field on the west side of the track 
the material was struck at a depth of only five feet. 

Samples for testing were taken from the west side of the cut at 
three different points, representing a distance of at least 200 feet. 

The kaolin as mined is light-bluish gray in color and has some 
limonite stains close to the surface. There is much quartz in the 
material and about 25 i was caught on a 100-mesh sieve in the wash- 
ing of the clay. 

Both the crude and washed kaolin are very refractory, barely show- 
ing signs of incipient fusion at cone 27. 

In burning, owing to its silicious character, the kaolin shows very 
little shrinkage. The sample tested burned white at cone 8. 

Kaolin is found on the property of Mr. Hooper, a. little over \ mile 
west of Leslie, and about \ of a mile south of the Baltimore and Ohio 
Railroad tracks, and near a branch of the high road. 

This is a material derived from the decomposition of granite and 
contains a considerable percentage of coarse quartz grains. It is 
overlain by 8 feet of sandy material. In washing it 38^ of the 
material was retained on the 100-mesh sieve and 5$ on the 150-mesh 
sieve. The material falls to pieces readily in water and could there- 
fore be washed without much trouble. The washed sample burns to 
a white color at cone 8, and has a shrinkage at this point of but 0, 
the air-shrinkage being 2$. When heated to cone 27 in the Deville 
furnace, it shows simply the beginning of incipient fusion, while the 
color is quite white. The tensile strength was extremely low as is 
the case in all kaolins and did not exceed ten pounds per square inch. 
This property being located so near to the railroad, should be capable 
of easy and rapid development. 



216 THE MINERAL RESOURCES OF CECIL COUNTY 

There is on the same property a considerable outcropping of buff 
kaolin, the material showing not only in a test pit, but also in the 
ditches along the roads. 

The crude material shows moderate refractoriness, becoming vis- 
cous at cone 30, in the Deville furnace. 

At Broad Creek, underlying the black Patapsco clay, there is a 
small outcrop of kaolin somewhat similar in appearance to that found 
in Sutton's cut near Perryville, but containing a larger quantity of 
iron stain. It is claimed that a first-class washed product was pro- 
duced here, but that the operations ceased on account of the material 
giving out. The kaolin crops out in a. pit on the south side of the 
road and also on the north side of Broad Creek. Overlying it is a 
hard layer of kaolin which has become cemented together and might 
perhaps serve as a datum plane in further search for kaolin in this 
region. At the time the deposit was worked, it is said that the water 
for the washing operation was obtained from Broad Creek, but it 
seems doubtful whether this stream would be able to supply enough 
water for the performance of the work all the year round. 

A very white looking kaolin is found on the property of Mr. I. R. 
Dean at the point § of a mile northeast of the town of ISTortheast and 
on the road to Elkton. There seems to be very little stripping 
necessary but in places the clay is somewhat buff in color. 

A coarse-grained kaolin is found along the Philadelphia, Wilming- 
ton and Baltimore Railroad about one mile southwest of Iron Hill, 
and has been used for lining cupola furnaces. 

Kaolin was also struck on the property of Mr. A. Thiess, at a point 
two miles clue north of Mechanics Valley. The material appears very 
white in color, and there is practically no stripping, at least this was 
the case in the test pits which had been sunk to prospect the material. 
Much of the kaolin is very white. 

Micaceous clay of a residual nature is found in Atkinson's cut on 
the Baltimore and Ohio Railroad, two miles west of Leslie. The 
exact thickness is not known. It i-, however, quite refractory, for at 
cone 27 it shows signs of only incipient fusion. 

An abundance of kaolin was found in sinking a well on the prop- 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XIX. 




FlG. 1.— outcrop of kaolin IN SUTTON cut, near perryville. 




Fig. 2.— FLINT MILL AND KILN, CONOW1NGO. 



MARYLAND GEOLOGICAL SURVEY 217 

erty of Frank Weeks, near Pleasant Hill. The material contained 
an abundance of micaceous scales. At cone 27 it burns white, with 
the merest trace of yellow, and is but incipiently fused. 

Kaolin is also known at Jackson's Baltimore and Ohio Railroad 
crossing north of Northeast. 

Flint and Feldspar. 

Quartz of sufficient purity and abundance to stimulate attempts at 
quarrying it for " flint " has been found in many places throughout 
the northern part of Cecil county, especially in the vicinity of the 
serpentine " barrens." It occurs in veins or dikes trending in a north- 
easterly direction from the Susquehanna, more or less nearly parallel 
to the boundaries of the different rocks. The presence of " flint de- 
posits " is indicated by the numerous boulders of white vitreous 
quartz which often appear honeycombed. The veins in which the 
quartz occurs cannot be traced for any considerable distance in Cecil 
county, and there are no bodies as large as those about Castleton 
across the river in Harford county. There are, however, several 
places where small openings have been made for quarrying the 
"flint," which is hauled to the mill at Conowingo. At the present 
time most of the flint ground at Conowingo comes from Harford 
county. It is customary to roast the blocks of quartz in the kiln 
shown in Plate XIX, Fig. 2, and then cool it suddenly by pouring 
water on the highly heated rock. This cooling causes a rapid con- 
traction, which in turn causes the rock to be filled with cracks which 
render the grinding much easier and more economical. The ground 
flour of flint is shipped in bags to the potteries located at Trenton, 
Xew Jersey, and elsewhere. 

Feldspar has been quarried from time to time in Cecil county. 
This mineral occurs in pegmatitic veins which are found in different 
parts of the highlands of the county underlain by crystalline rocks. 
These veins or dikes are best exposed along the Susquehanna river 
in the northwestern part of the county, as already described by Miss 



218 THE MINERAL RESOURCES OF CECIL COUKTY 

Bascom. 1 The dikes which have been opened for feldspar cut the 
serpentine, norites, and gabbro and occur along Octoraro Creek and in 
the vicinity of Rock Springs On Octoraro Creek, between the paper- 
mill at the fork in the road and the State line there are three such 
dikes. The pegmatite is quarried on the west side of the creek, 
about one and a half miles east from Rock Springs, on the Taylor 
farm and is said to have yielded some 10,000 tons of " spar," which 
was shipped to Trenton, New Jersey, and Liverpool, Ohio, for use 
in the pottery works. At present these quarries are idle. 

The only active quarry now in operation is situated a short dis- 
tance east of Rock Springs near the old Tweed and Riley quarries 
which were abandoned three or four years ago. The present small 
opening showed a fair body of clean "spar" which was uncovered in 
1901. The small amount of feldspar quarried is hauled to Cono- 
wingo and shipped to Trenton. 

There are numerous small abandoned openings in the region of 
Goat Hill and near Sylmar. These deposits are generally just north 
of the State line in Chester county, Pennsylvania. Since the feld- 
spar here is in smaller bodies and is less disintegrated than in the 
Brandy wine area they cannot be worked as cheaply and hence can- 
not compete successfully with the latter deposits. 

Iron Ore. 

The presence of iron ore of greater or less richness was early recog- 
nized in the area about the Chesapeake Bay, for it is recorded that 
as early as 1608 Captain John Smith had sent two barrels of iron- 
ore specimens back to England for examination. It is quite possible 
that some of these specimens came from Cecil county, although this 
fact cannot be proven. It was not, however, until nearly a hundred 
years later that the iron-ore was worked in any degree. By 1701 
when the Welsh tract, including Iron Hill and the area about Elkton, 
was granted it had been recognized thai there existed deposits of 
some possible value as iron ore and somewhat later the Welsh opened 
small shafts in what is now known to be a silicious iron ore, for ac- 

1 pp. 101-103. 



MARYLAND GEOLOGICAL SURVEY 219 

cording to Johnston x " miners employed in the ore pit on Iron Hill, 
came upon one of the galleries made by the "Welsh miners, and dis- 
covered a rude shovel and pick and a small tallow candle, the wick 
of which was made of flaxen yam. The candle, though probably 
a century old, was in a good state of preservation, but the shovel and 
pick w r ere so badly rusted that the former could be 'readily picked 
to pieces with the thumb and finger." 

Although these deposits of iron ore have been found in various 
portions of the county it seems probable that only a very small 
amount of the ore used in the various iron-works which were for- 
merly of so great importance in Cecil county was found in the neigh- 
borhood of the furnaces. The records so far as they are known indi- 
cate that most of the ore was shipped by water to the Cecil county 
furnaces from deposits in Harford, Baltimore, and Anne Arundel 
counties. 

The iron-w T orking industry in the county is now practically a thing 
of the past, owing to the complete change in methods of working ore 
and to the discovery of richer deposits elsewhere. It is of interest, 
however, to bring together a few of the facts which have been gleaned 
regarding the industry which reduced the raw mineral wealth of the 
State to manufactured products that aided greatly in the building up 
of the community. Few new facts have come to light in recent years 
and the following review has been drawn almost entirely from the 
papers of Alexander, Johnston, Swank, Whitely, and Keyser. 2 

The earliest record which we have of any iron work within the 
county is contained in a deed dated 1716, which conveyed the iron- 
works located near the "main falls of North East" from Robert 
Dutton to Richard Bennett. This mill v T as probably the forerunner 

'History of Cecil County, Elkton, 1881, p. 108. 

2 Alexander, "Report on the Manufacture of Iron; addressed to the Governor of 
Maryland," Annapolis 1840. 

Johnston, "History of Cecil County," Elkton, 1881. 

Swank, "American Iron Industry from its beginning in 1619 to 1886," Min. Re- 
sources U. S., 1886 pp. 23-38. 

Keyser, "The Iron Industry," Maryland. Its Resources, Industries and Institu- 
tions, 1893, pp. 100-112. 



220 THE MINERAL RESOURCES OF CECIL COUNTY 

of the McCullough Iron Company's works. There were also forges 
worked on Christiania Creek in 1725. The most important works 
were situated at Principio where they were erected by the Principio 
Company which was organized in 1722 by Joseph Farmer, an iron- 
master from England. With him were associated William Russell, 
Joshua Gee, Stephen Onion and John Huston, as the chief promoters. 
The stock w ? as at first in the hands of Englishmen but very soon after 
its organization the Company came into the more or less complete 
control of the Gilpin and Washington families. This Company soon 
outranked all others in America in the manufacture of pig and bar 
iron, being the proprietor of three furnaces and two forges in Mary- 
land, and of the Accokeek furnace in Virginia. 

The original w r orks built by the Principio Company were situated 
about 150 yards further up the stream than the present plant, which 
was built by ]\Ir. Hughes about 1800. The forges were very rude 
affairs. The blast was made by means of curious circular bellows 
which was operated by means of a water-wheel, each bellows and 
hammer having a water-wheel of its own. These, however, were 
regarded as equally well equipped with any works of their kind 
on the continent. The plant built by Hughes was injured and par- 
tially destroyed by the British during the war of 1812, but was 
subsequently repaired and carried on by the same proprietor until 
1817-18. It then went out of blast until 1836, when it was pur- 
chased, together with a large tract of land, by Messrs. G. P. Whit- 
taker and Company, who at present own the property which is now 
occasionally inactive. 

The works at Northeast have part of the time been under the 
control of the Principio Company, but in later years have been owned 
by various persons, including the McCullough Iron Company, who 
la-t operated the works which are now inactive. 

The old mill on the Big Elk about a mile west of Appleton was 
built in 1810 and was operated for several years by Parke Brothers, 
producing boiler-plate iron from blooms and muck bars. The firm 
of Parke, Smith and Company succeeded to the business in 1858 and 
altered the mill into a sheet mill, but were later forced to suspend 



MARYLAND GEOLOGICAL SURVEY 221 

operations because of the competition of mills more favorably situ- 
ated. 

Chrome. 

Along the northern limits of the county from Conowingo and 
Bald Friar on the Susquehanna eastward for a distance of about 
fifteen miles extends a series of " barrens " underlain by serpentine, 
which in many instances has yielded rich deposits of the unusual 
mineral chromite, an oxide of the metal chromium. As early as 
1827 it was recognized by Mr. Isaac Tyson, Jr., that the black, 
metallic mineral chromite was the same as that which was bringing 
a hundred dollars a ton in the European market. It was not, how- 
ever, until a year or so later that chromite-bearing serpentines were 
traced into Cecil county and thence across the State boundary into 
Lancaster county, Pennsylvania. The richest deposit found in all 
this belt lies just across the State line five miles northwest of Rising 
Sun on the Wood farm. At the surface the ore body was 30 feet 
long and 6 feet wide and the ore so pure that 10 cubic feet produced 
a ton of chrome ore averaging 54 per cent chromic oxide. At one 
time almost all of the chromic ore used the world over was produced 
from this single mine, which shipped as high as 400 or 500 tons each 
month. At first the ore was hauled by wagon to Port Deposit, where 
it was loaded into vessels and sent either to Liverpool or Baltimore. 
Later when the central division of the Philadelphia, Wilmington and 
Baltimore railroad was built through Rising Sun it was customary 
to load at that point, shipping the material to Baltimore by rail. 
This mine was worked almost continuously from 1828 to 1881, when 
operations permanently ceased. There was no work, however, dur- 
ing the years 1868 to 1873. The operations ceased partly because of 
the depth to which the mine had gone, but more especially because 
the ore could be obtained more cheaply from the rich deposits dis- 
covered near Brusa, a small town about 75 miles southwest of Con- 
stantinople, which at present supply the chrome ore for the demand 
of the entire world. 

All alona: either side of the Mason and Dixon Line between Rock 



222 THE MINERAL RESOURCES OF CECIL COUNTY 

Springs, Maryland, and Pleasant Grove, Pennsylvania, are a series 
of abandoned openings which have been made in search of chrome 
ore. Some of these were successful and have received local names, 
among which may be mentioned the " Line Pit," which was owned 
in part, and worked by th^ Tysons; the Jenkins Mine, Low's Mine, 
owned and for some time worked successfully by Andrew Low and 
Benjamin Gibson; "West Pit, and Brown's Mine. From the very 
first all of the chrome openings were operated by the Tysons or their 
product was controlled by the trade conditions which were dominated 
by them. 

Chrome sands were found, some of them of considerable richness, 
in the stream-beds and valleys of the small streams draining the ser- 
pentine area and they have been worked spasmodically for the 
chrome ore which became concentrated in them because of the inde- 
structible character and weight of the chroinite compared with the 
minerals with which it is associated in the parent rock. The last 
worked deposit of chrome sand was on a small tributary of Stone 
Run at a point just south of the State line two miles north of Rising 
Sun. Even this was abandoned in 1900. 

The industry which was established in Baltimore through the dis- 
covery of the deposits of chrome ore in Maryland has continued even 
after the local ore has been replaced by that from Asia Minor. 
Chrome ore has been found also at various points within the United 
State, notably California, but the American ore in all instances is no 
longer mined because it is impossible to compete with the Asia 
Minor product. 

Gold. 

It has long been known that gold occurs in finely disseminated 
particles in many of the crystalline rocks of the Piedmont Plateau 
and numerous attempts have been made to locate areas of sufficient 
concentration to give a good return for the capital and labor invested. 
The fact that there is a popular conception that money is made from 
the mining of gold wherever the latter is found has given strong 
inducements to unscrupulous men to promote gold excitements and 



MARYLAND GEOLOGICAL SURVEY 223 

the consequent gold companies throughout various portions of the 
Piedmont area. Often these gold scares are without the slightest 
reason beyond that of the cupidity of the promoters, but many of the 
attempts to develop a successful industry in the mining of gold in the 
East have been stimulated through ignorance and lack of appreciation 
of the fact that there is no more profit in mining small quantities of 
gold at large expense than in farming poor lands with large amounts 
of fertilizer for a small crop. 

Cecil county has not escaped the excitement and often harmful in- 
fluences of the supposed discovery of gold in payable quantities within 
its borders. A few years since it was supposed by some prospectors 
that the serpentine " barrens " in the northwestern corner of the 
county carried large pockets of gold and the Klondike Gold Company 
was formed to control the mineral properties and operate the mines 
of the tract. The promoters of this project were fortified in their 
position by reports of analyses apparently showing that the rock was 
really a well-paying ore. The promised return for the investment 
in land and the unusual prices offered for property produced tem- 
porary demoralization, and in a few instances when the disappointing 
failure came, produced more or less suffering. 

It is very doubtful if gold will ever be found in paying quantities 
within the confines of Cecil county although it is not at all im- 
probable that excitement may be caused now and then by the finding 
of minerals of yellow color and glistening surface, or even by the 
finding of true gold. In order to warrant extensive development 
or the investment of money it must first be shown that the material is 
truly gold, and, second, that it occurs in sufficiently rich masses to 
make the ore worth more per ton than it costs to secure the mineral 
rights, install the machinery necessary and pay for getting out the 
ore. 

Road Materials. 

Cecil county is well supplied with materials for making first-class 
roads throughout its limits but up to the present time they have not 
been used to any extent. Following the geological division between 



224 THE MINERAL RESOURCES OF CECIL COUNTY 

the crystalline rocks and the Coastal Plain deposits, is a separation 
in the character of the various road materials. As already described, 
this line follows approximately the line of the railroads from the 
Susquehanna to the Delaware line. To the northwest of the boun- 
dary the road materials are crystalline rocks of various sorts described 
in the following paragraphs, while to the south and east the material 
suitable for the construction of good roads consists of gravels and the 
oyster shells gained from the Bay. 

Among the various rocks distributed over the northern and western 
portions of the county two are of particular value as road materials 
and their area! distribution may easily be gained by a glance at the 
geological map accompanying this report. These are the gabbro and 
the granite. 

GABBRO. 

Beginning in the vicinity of Conowingo there extends eastward 
a well-defined belt of trappean rock which is well adapted both by 
its cementing and wearing qualities to the construction and main- 
tenance of high-class macadam roads subject to considerable wear. 
This material has been used somewhat in the repair of local highways 
but in almost every instance it has not proved satisfactory for more 
than a short time, either because the pieces used have been too large 
or because the proper sized pieces have been put upon a road-bed 
which had not previously been prepared properly to receive it. To 
gain the best results from this gabbro rock it is necessary to use it in 
layers a few inches thick distributed and carefully rolled one by one. 
On the lower course the rock fragments should be between 1^ and 
2^ inches in diameter, while the upper stone should be spread upon 
the well-rolled lower courses, and the individual pieces for the upper 
course should not be larger than from f to 1^ inches in diameter. 
When properly rolled the first course should be 4 inches thick and the 
second, or upper, course 2 inches in thickness. When this manner 
of distributing the road material is employed it is found that the 
material from the gabbro belt of Cecil county will give most excel- 
lent roads well adapted to the wants of the people. 



MARYLAND GEOLOGICAL SURVEY 225 

No quarries have as yet been opened in the gabbro and it has 
never been placed upon the market to supply road material for other 
areas within the county. If it were favorably situated in the vicinity 
of some large city much of the material might pay for its quarrying. 

GRANITE. 

To the southward from the gabbro belt is an area of granites and 
gneisses which are best exposed in the granite quarry at Port Deposit 
already described in the discussion of the building-stone. Here, in 
the preparation of the raw material for the market, there are left 
from the blocks used in building, numerous angular fragments and 
stained blocks which are now being utilized as road materials and 
gravel for walks and driveways. A stone-crusher has been erected 
and it is now crushing all of the material not used as building-stone. 
The industry which has arisen in road material has rapidly increased 
and now a considerable business is conducted in the material pre- 
pared from what was formerly regarded as worthless rubbish which 
must be removed at a tax on the quarrying industry. 

The road material at this quarry is shown by the test published in 
the Highway Report of the Survey to be high in its coefficient of wear 
when compared with other granitic rocks. Its cementing power, 
however, is somewhat low. 

GRAVEL. 

Deposits of gravel suitable for road material are found in various 
places in the southeastern part of the county. They have not been 
as thoroughly developed as they might be. Gravel on the road fur- 
nishes an excellent material for surfacing the ordinary dirt roads. 

Oil. 

The presence of oil in Cecil county has often been claimed and 

more or less interest has been aroused by the efforts winch have been 

made to find it. All such attempts to strike oil in paying quantities 

within the confines of Cecil county are doomed to failure, although 

15 



226 THE MINERAL RESOURCES OF CECIL COUNTY 

small indications of oil may be encountered at the surface or in wells. 
The conditions necessary to the formation and preservation of work- 
able deposits of oil are well understood and these conditions are 
known to be lacking in Cecil county. Small films of oil may be 
formed now and then from the decaying fossil remains but the 
amount so formed will be small while the broken and permeable char- 
acter of the deposits in which these fossils are found offers no oppor- 
tunity for the concentration or retention of the small amounts of oil 
so formed. These facts clearly show that the hope of making legit- 
imate profits from oil investments in Cecil county is without any 
reasonable foundation. 

List of Operators in Mineral Products in Cecil County. 
Clay — Brick and Tile. 

John Gilpin Elkton. Tbe Acme Red Brick «fc Fire 

W. R. Grosb Northeast. Brick Co Northeast. 

Cecil Fire Brick Co Northeast. Wakefield Fire Brick Co Northeast. 

Green Hill Fire Brick Co Northeast. Maryland Clay Co Northeast. 

Clay Mined and Sold. 

Win. J. McDowell Northeast. Chas. W. Simpers Northeast. 

Flint and Feldspar. 

B. G. & J. C. Smith Conowingo. G. W. Stevenson Conowingo. 

F. G. Sutten & Co Conowingo. J. W. Walker Sylniar. 

David C. Bentz Oak wood. 

Granite. 

Perry ville Granite Co Aikin. Consolidated Granite Co. . .Port Deposit. 

McCleuahan Granite Co... Port Deposit. 



THE SOILS OF CECIL COUNTY 

BY 

CLARENCE W. DORSEY and JAY A. BONSTEEL 



Introductory. 



Cecil county is the most northern of the Eastern Shore counties of 
Maryland. It lies between 75° 46' and 76° 14' west longitude and 
39° 22' and 39° 44' north latitude. The greatest width is 25 miles, 
while the length north and south is practically the same. On its 
northern border and for a short distance along its eastern boundary 
the county comes in contact with Pennsylvania. Delaware lies east 
of the greater part of the county. The broad Susquehanna river 
and Chesapeake Bay bound the county on the west, while the Sas- 
safras river separates it from Kent county on the south. The area of 
the county, exclusive of the broad waterways, is about 375 square 
miles (240,000 acres). 

Agricultural Conditions. 

As might be expected from the diversified surface, the agricul- 
tural conditions are quite distinct and characteristic in the respective 
portions of the county. The great range in the character of the 
soils, from those absolutely barren to the most productive, is probably 
the greatest factor in the diversified agricultural conditions. While 
formerly there were many large farms in the county, these have 
been divided and sub-divided until now the average sized farm 
does not contain more than from 100 to 120 acres. These farms 
vary greatly in value, according to the improvements and char- 
acter of soil. In some of the poorer portions unimproved land 
brings but a few dollars per acre, and there is no great demand for 
it at any price. In the better sections good farm land brings from 



228 



THE SOILS OF CECIL COUNTY 



$40 to $75 per acre. In the more prosperous farming sections the 
improvements are good and prove the thrifty and industrious char- 
acter of the farmers, but in the gravel and clay hills of the central 
part the improvements are poor, consisting of ragged, dilapidated 
fences, small dwelling houses, and patched-up barns and sheds. In 
the good farming districts the dwelling houses are comfortable, some 
of them being quite pretentious, while the barns and other buildings 
are in keeping with the general character of the country. Xeatly 
trimmed hedge fences form an attractive feature of the farm sur- 
roundings. Many of these farms are tilled by the owners. This 
is especially the case in the northern part of the county, but there 
are also a large number of farms which are in the bands of tenants 
who are not greatly interested in improving the farms and in bring- 
ing them to a high state of cultivation. 

A large portion of the county is still forested and uncultivated. 
While originally the entire county was thickly timbered with various 
kinds of hard-wood and soft-wood trees, none of the original growth 
is left standing. In many parts the light timber growth has been 
removed regularly every few years for making charcoal and also for 
use in melting the ores which were formerly extensively smelted. 

Wheat, com, timothy and clover are the main crops, and these are 
grown over the entire county. Truck is grown to some extent, but in 
the northern central part, growing late crops for canning purposes 
has for a long time been an important industry. Tomatoes and corn 
are the principal crops grown for this purpose, and for a long time 
Cecil and Harford counties have ranked among the prominent tomato- 
canning districts of the country. Competition with the Middle 
Western States has somewhat diminished the proportions of this 
industry, but it still is a large source of revenue to the farmers and 
to the hands employed during the growing season. The canneries 
are all small, situated short distances apart, and are run only for a 
few months in the late summer and the early autumn. If the 
small, scattered canneries were grouped into larger and better 
equipped factories, more centrally located, operated from early spring 
until late fall, and were prepared to can a greater variety of products, 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XX. 




FIG. 1.— WEATHERING OF GRANITE INTO CECIL LOAM, NEAR FRENCHTOWN. 








¥ 



\Wm 



__*_v 


! 

s 




#|fv- 







Fro. '2.-CRYSTALLINE ROCKS OVERLAIN BY GRAVEL. 
AGRICULTURAL VIEWS IN CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 229 

they could be much more profitably operated. At present the profits 
are divided among a number of small, poorly equipped plants, which 
tend to cripple the industry rather than to encourage it. 

The fruit industry of Cecil county also deserves mention, as large 
quantities of peaches and pears are annually placed on the markets. 
Although the cultivation of apples and cherries is less, these, as well 
as small fruits, are grown both for home consumption and for the 
markets. 

The market advantages of Cecil county are good, for with the rapid 
and abundant transportation facilities the county enjoys, the products 
can soon be placed on sale in the large Eastern cities. The county is 
midway between Baltimore and Philadelphia, and these cities con- 
sume the greater part of the farm products. There are two main 
lines of railroads which cross the county between these cities, in 
addition to branch lines of one of these roads, which furnish an easy 
outlet for the northwestern part of the county. The southern part 
of the county, while it has no railroads, possesses fine waterways, and 
consequently cheap water transportation to Baltimore and Philadel- 
phia. Several points in the southern part are reached by daily steam- 
boats as well as by sailing vessels of various descriptions. 

No systematic efforts have been made to equip the county with 
roads built on scientific principles, and the majority of the roads are 
not in very good repair. Some of them have been made of broken 
stone and gravel, and these are above the general average of country 
roads. Others, again, are deep and sandy, making the hauling of 
heavy loads over them almost impossible at any time of the year. 
The roads are all free, are maintained at the expense of the county 
and connect all of the towns and villages, with frequent intersecting 
cross-roads. 

Soil Formations. 

The soils of Cecil county range from barren to exceedingly rich and 
productive lands, and from coarse sandy soils to stiff, intractable 
clays. 



230 THE SOILS OF CECIL COUNTY 

AREAS OF THE DIFFERENT SOILS. 



Soils. Acres. 



Cecil loam 52.600 

Sassafras loam 50,500 



Per 

cent. 



Soils. 



2I.'.< Susquehanna clay. 
21-0 Cecil mica loam. 



Acres. 



Per 
cent. 



11,000 4.5 

10,000 4.1 



Norfolksand 46,600 19.4 Elktonclay 7,000 2.U 

Susquehanna gravel 45,600 18.7 Conowingo clay 3,000 1.2 

Cecil clay 12,500' 5.2 Conowingo barrens 2.000 .8 



CECIL LOAM. 

The Cecil loam constitutes a type of soil characteristic of portions 
of the Piedmont Plateau, not only of Cecil county, but also of large 
areas of northern central Maryland and adjoining states as far south 
as the Carolinas. Beginning at the gorge of the Susquehanna river, 
in the western part of the county, it continues in an unbroken area 
several miles in width to the Delaware line on the eastern border. 
Along its southern border it presents a ragged outline, being buried 
under the outlying gravel deposits of the Coastal Plain formations. 
On the northern boundary these formations merge into the other for- 
mations of the Piedmont Plateau, with no sharp lines of demarcation 
of the soils or decided change in the surface features of the country. 

The topography of this formation partakes largely of that of the 
Piedmont Plateau. Along the Susquehanna there is a steep descent 
of 200 feet or more from the upland to the river bed, steep, rocky 
hills characterizing this portion of the formation. The remainder 
of the formation is a rolling upland, broken by the steep, narrow 
valleys of the various streams which cross it. Many parts of this 
formation are those which have been referred to as the most level 
of the Piedmont Plateau in Cecil county. The drainage of this en- 
tire area has for a long time been thoroughly established, so that there 
are no swampy areas; for the formation is not only well drained but 
also well watered by the many small streams which traverse it in a 
southerly direction. 

The Cecil loam is derived from the slow weathering of the granites, 
gneisses, schists, etc., which occur in the Piedmont Plateau. Situ- 
ated south of the limit of ice action during glacial times, the slow 
processes of subaerial decay have had ample time to accumulate a soil 



MARYLAND GEOLOGICAL SURVEY 



2:51 



covering, shallow or deep, depending on the location with reference 
to the washing influence of rains. These residual soils are all derived 
from the rocks which underlie them, or at most have been trans- 
ported but very short distances. The soils consist of yellow and 
brown loams, slightly sandy, and about 10 inches in depth. The sand 
consists generally of sharp, angular grains of quartz, and frequently 
small bits of the undecomposed granite or gneiss may be found mixed 
with the soil particles. The subsoils are lighter in color and contain 
a greater percentage of clay. They may be classed as light, yellow- 
clay loams. Generally, these clay loams have a depth of 36 inches 
or more, but they often grade into loose masses of decomposed gneiss 
or granite at a depth of 30 inches, or occasionally at a depth of even 
20 inches. In places the soil covering has a depth of several feet, but 
these are rare occurrences. On the surface there is usually present 
an appreciable amount of broken quartz and occasionally pieces of 
granite, gneiss, schist, gabbro, or any of the rock formations from 
which the soils are derived. Although the amount of stones may at 
times equal 40 per cent, generally the amount is much less and does 
not seriously interfere with cultivation. These stones range from 
one-half inch to 6 inches in diameter. 

The following table gives the mechanical analyses of soils and sub- 
soils of typical samples of Cecil loam: 

MECHANICAL ANALYSES OF CECIL LOAM. 



No. 



Locality. 



Description. 



4029 Providence, 1 mile to 12 inches 

SW. 

4232 Farmington, 2 miles Yellow loam, to 

NE. 6 inches. 

4030 Plum Point. 1 mile 12 to 30 inches 

SW. 

4233 Subsoil of 4232... 



Stiff yellow loam, 
6 to 24 inches. 



O 



P. ct. 
5.55 

5.18 

3.76 

4.81 



O 



P. ct. P. ct. 

3.02 5.74 

3.36 8.52 
2.21 , 5.57 
4.54 I 10.01 



•310 

1° 



P. ct. 
12.64 

6.26 

4.18 

6.74 



,_, 





s 





+a 





»~2 


a 








10 


a 

03 




<=> 





•a 

a 


02 

3 6 




10 




93 a 


00 





.5 9 


-+J 


rH 


> 


en 


P. Ct. 


P. Ct. 


P. ct. 


14.92 


13.90 


32.96 


14.10 


11.95 


31.67 


11.91 


13.21 


40.22 


13.79 


11.61 


27.19 



.S3 



P. ct. 

11.32 

19.32 
19.27 

21.01 



232 THE SOILS OF CECIL COUNTY 

These soils are classed as good farm lands, and, while they are not 
naturally strong soils, they can by careful management be made very 
productive. Generally, they are deficient in organic matter, but this 
can be remedied by liberal applications of well-rotted stable manure 
or by the plowing under of green manure. As now cultivated too 
much money is expended for commercial fertilizers. By saving and 
applying stable manures these soils could be brought to a higher 
state of productiveness than is attained by the use of often inferior 
brands of commercial fertilizers. Originally these soils were thickly 
covered with a heavy growth of timber, embracing all the common 
hard-wood varieties. The greater part of the area is now cleared and 
under cultivation. 

Tomatoes are grown on this soil in large quantities for canning 
purposes. Almost every farm, especially in the neighborhood of 
Rising Sun and Zion, has a field of several acres each year in tomatoes. 
On account of the loamy condition, these are probably the finest corn 
soils in the county, and it is said that from 40 to 60 or even 80 bushels 
per acre can be grown. Wheat produces well, from 20 to 25 bushel? 
being a good average crop in favorable seasons. Fifty bushels of oats 
can be harvested in good years, and clover and timothy make good 
crops. For many years Cecil county had a reputation in Baltimore 
markets for the fine quality of hay it produced, and it was on Cecil 
loam and Cecil clay that it was principally grown. Mixed clover 
and timothy seed are sown, but the clover rarely lasts longer than 
one year. The usual rotation practiced on these soils is wheat two 
years, followed by timothy and clover, which usually lasts two years, 
then corn, after which again comes wheat. When oats or tomatoes 
are grown the five-year rotation is varied somewhat, and occasionally 
the timothy is allowed to stay two years after the clover fails. This 
depends somewhat on the effect of the winter on the crops. Lime 
is applied to these soils and the good effects are noticed for several 
years afterwards. It is often observed that the lime has the effect 
of sweetening the soils and checking foul or rank growth. 

The farms on these soils are usually comparatively small, and are 
in most cases tilled by the owners; hence they are kept in good shape 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XXI. 




FIG. 1.— characteristic topography in susouehanna gravel area. 




Fig. 2.-TYPICAL FARM IN CENTRAL CECIL COUNTY 



AGRICULTURAL VIEWS IN CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 233 

and the people are in a generally prosperous condition. Some of the 
best improved farms of the county are located within the limits of this 
soil formation. 

CECIL CLAY. 

This formation, like the one just described, is found in the Pied- 
mont Plateau region of Cecil county. The formation occurs in sev- 
eral areas scattered over the northern half of Cecil county. There 
are 11 of these areas, but the largest and most important are situated 
in the extreme northern part. The surface of the Cecil clay is prob- 
ably more rough and broken than the Cecil loam, although there are 
some areas where the gently rolling character of the country is a rule. 
The broken and hilly areas of this formation are along the Susque- 
hanna river and the Octoraro and Conowingo creeks. A few of the 
smaller areas of this formation form prominent hills in the Coastal 
Plain part of the county. Doubtless these hills were once covered 
by the gravels which cap the surrounding hills, but subsequent erosion 
has removed this coating and they are now isolated areas entirely 
surrounded by the unconsolidated sands, gravels and clays of the 
Coastal Plain. Grays Hill, 2 miles northeast of Elkton, furnishes 
a striking example of the isolated occurrence of this formation. This 
hill rises considerably over 150 feet above the surrounding country, 
which consists of broad terraces and low, marshy areas characteristic 
of this section of the Coastal Plain country. Plate XXI, Fig. 1, 
shows clearly the relations of Grays Hill to the surrounding country. 

These soils are also residual, being derived from the rocks which 
underlie them. The Cecil clay is for the most part derived from the 
weathering of the hard, igneous rocks, such as gabbro and meta-gabbro. 
These are dark-colored rocks, which weather comparatively slowly 
into characteristic spheroidal masses. These large, rounded boulders 
are thickly scattered over the surface in some places in the Cecil clay. 
These stony areas are quite abundant on the upland just east of the 
Susquehanna river. Here the boulders are so thickly strewn over 
the ground that fields of several acres are often uncultivated on 
account of them. They vary from a few inches to many feet in 
diameter and are often spoken of as " niggerheads." 



234 THE SOILS OF CECIL COUNTY 

The soils of the Cecil clay consist of heavy reddish loam, to an 
average depth of 10 inches, underlain by red clay loam, which grade 
into stiff red clay. These soils are easily distinguished by their deep 
red color when in a moist condition. They are seldom over a few 
feet in depth and pass into broken pieces of gabbro and other rocks, 
from which they are derived. Generally there is a trace of broken 
quartz fragments scattered on the surface and mixed with the soils. 
Often there are small amounts of broken pieces of angular stone, 
rarely exceeding a few inches in length. These soils are much 
heavier than the Cecil loam and rank as strong clay soils, capable of 
standing hard farming, and also capable of being brought to a high 
state of productiveness. While the soils of this formation are gener- 
ally quite uniform wherever found, the areas northeast of Calvert 
and east of Appleton partake somewhat of the nature of the soils 
of the serpentine clay (Conowingo clay) as far as their productiveness 
is concerned. There is doubtless some mixture with the serpentine 
clay, but as they more closely resemble the Cecil clay in texture and 
general characteristics they have been correlated with this formation. 

The Cecil clay soils are generally classed with the Cecil loam as 
regards fertility, but by proper cultivation they can be made far more 
productive, and they are not so easily exhausted. It is said that one- 
half of the fertilizers necessary on the Cecil loam will suffice on these 
soils. Lime is used with excellent results, and commercial fertilizers, 
especially phosphates, are used in addition to frequent applications 
of stable manures. 

The Cecil clay is well adapted to wheat and grass and produces 
large crops. Wheat will yield from 20 to 30 or even 40 bushels per 
acre in good years, and from 1 to 2 tons of timothy and clover hay 
can bo harvested. From 50 to 60 or even 80 bushels of corn can be 
grown in favorable years, and yields of from 50 to 60 bushels of oats 
are reported. Tomatoes for canning purposes also produce well on 
these strong red clay soils, and from 200 to 400 bushels per acre can 
be grown with careful treatment and with favorable weather condi- 
tions. Apple trees make a healthy growth and bear well, but peaches 
and pears do not succeed. The farms are seldom large in this forma- 



MARYLAND GEOLOGICAL SURVEY 235 

tion, but are improved, well kept, and indicate a generally prosperous 
condition. 

CECIL MICA LOAM. 

Like the formation just described, the Cecil mica loam also occu- 
pies an area in the rolling uplands of the Piedmont Plateau. There 
is but one occurrence of this formation in Cecil county, and that is 
along the northern border in the eastern part, where Maryland comes 
in contact with Pennsylvania on its northern border. This area, is 
nearly 10 miles in length, and from 1 to 2 miles in width. The 
surface is rough and broken along Big and Little Elk and Christiana 
creeks; otherwise it is level or gently rolling. The uplands may 
rise from 200 to slightly over 400 feet in elevation. 

The soils are also residual, having been derived from the decom- 
position of gneiss and schist, which contain, among other rock form- 
ing materials, large quantities of mica. In the soils this mica appears 
in broken fragments, from the tiniest bits to particles of over a half 
inch in diameter. It is so abundant as to make the soils fairly sparkle 
in the sunlight, and on the soft dirt roads it floats away in the breeze 
with other dust particles. This feature has given the name to the 
soils, and they are commonly referred to as the red and white isin- 
glass lands. The soils of this formation are light loams, lighter in 
texture than the Cecil loam, and they generally have a brownish or 
yellowish-brown color. They contain considerable sand, but are 
mostly composed of silt with small amounts of clay. The subsoils, 
from a depth of 10 to 30 inches, consist of reddish-yellow clay loam, 
which also contains a large percentage of finely divided mica of the 
muscovite variety. In texture the subsoils differ little from the 
soils, although they may contain a slightly increased percentage of 
silt. At an average depth of 30 inches the subsoils grade into the 
loose, decomposed gneiss, granite, schist, or whatever rock the soil 
is derived from. These soils are always warm and dry, and possess 
excellent underdrainage. 

The mechanical analyses of typical soils and subsoils are given in 
the table following: 



236 



THE SOILS OF CECIL COUNTY 



Ml.' BANICAL ANALYSES OF CECIL MICA LOAM. 



No. 



Locality. 



Description. 



42'" Lewisville, 3 4 mile S. Brown micaceous 
loam, to 10 



4223 Subsoil of 4222. 



4227 Appleton, 2 miles 
NW. 



inches. 
Yellow loam, 10 

to 36 inches. 
Yellow loam, 8 

to 36 inches. 



a 




>a 


o 


rt 


o 

+3 


mm. 
l.OOOl 


S 


o 


43 

IC 


o 
o 


© 









o 

















•o 


o 


+3 

s 

a 


z 


£ 

03 

CO 




o 

CS 


R 
to 

§g 


05 to 0.0 

0.005 t( 


£ :' : 


> 




•3C>5 

4>d 


D £ 


r-'- 


° >;S 


bi O 


2 


« fl 


.5£ 


a-o 


- sS 


o 


a 


o 


s 


P. ct. 


> 


aa o 


?. ct. 


P. ct. 


P. ct, 


P. ct. 


P. ct. 


P. ct. P. ct. 


4.V0 


1.72 


10.37 


5.87 


17.64 


15.64 


35.10 8.59 


6.86 


2.69 


6.44 


5.26 


22.41 


14.20 


29.16 12.78 


4.07 


4.75 


7.93 


4.92 


10.13 


9.24 


42.93 15.50 



These soils compare favorably with the Cecil loam, as far as their 
productiveness is concerned. They are naturally fertile; but they 
must be managed with care or their fertility is soon lost. They con- 
tain some quartz rock and broken pieces of gneiss and schist on the 
surface, but not so large an amount as the (Veil loam. Generally, 
they are mellow soils, easy to till, and respond quickly to the appli- 
cations of manures or commercial fertilizers, such as tankage, ground 
bone and phosphates. 

Corn, wheat and grass are grown on these soils, and the yields 
equal those of the Cecil loam. From 15 to 25 and 30 bushels of 
wheat, 45 to 60 bushels of corn, and 1 to 2 tons of hay are the crop 
yields in favorable seasons. Tomatoes and corn are grown for can- 
ning purposes. The crop rotations practiced are practically the 
same as on the other soils. As a general rule small, well-improved, 
and carefully cultivated farms are found in this formation. 



CONOWINGO BARRENS. 

We now come to a class of residual soils occurring on the uplands 
of the Piedmont Plateau, which, although not differing greatly in 
texture from the soils just described, are found to be well-nigh worth- 
less when their productiveness is considered. This is the type of 
soil known as the Conowingo barrens. Four small areas are found 
in tlie extreme northwestern corner of Cecil county. Two of these 



MARYLAND GEOLOGICAL SURVEY 237 

areas are of some size, but the others contain only a few acres. The 
largest of these areas begins at the Susquehanna, a half mile north 
of Conowingo, and continues northeast to the Pennsylvania boundary. 
The other areas are situated near by. All of the areas of this forma- 
tion are rough and hilly. Conowingo and Octoraro creeks flow 
through both areas, which accounts for the rough and broken surface 
of the country. 

This soil is derived from the weathering of serpentine, which is an 
altered eruptive rock of a dark greenish color. The soil generally is 
a light-yellow or whitish-looking loam, but in places it is almost 
black. The top soil occasionally has a depth of 8 or 10 inches, and 
is underlain by a yellowish-brown loam subsoil to a depth of 36 
inches. The soil is generally much shallower, and in the case of 
the barren hills of this formation the rocks are devoid of any trace 
of soil covering except that caught in the pockets and crevices of 
the rocks. Frequently, even on level or lightly rolling areas, the 
soil covering may not exceed a few inches in depth. These soils, 
as seen from the mechanical analyses of samples collected, are not 
essentially different from many of the productive upland soils; but 
they are unproductive, and in extreme cases will not produce any- 
thing in a natural state except a stunted growth of small pines and 
knotty oak trees. At the best, they are stubborn and unproductive, 
and although many reasons have been assigned for their sterility, 
none seem altogether satisfactory. Professor Merrill, 1 in speaking 
of the Chester county barrens, just across the State line in Pennsyl- 
vania, says that these soils are derived from the slow decomposition 
of peridotites, rocks rich in iron-magnesium silicates, but almost 
wholly lacking in lime, potash, or other desirable constituents. 
Hence the soils derived from such rocks are naturally devoid of 
nutrient matter and can support only a scanty growth of grass and 
stunted shrubs. The main reason which may be assigned for their 
unproductiveness is the large percentage of magnesia which they 
contain, and their slight depth. The analyses of these soils show 

1 Rocks, Rock-weathering, and Soils, 1897. 



238 



THE SOILS OF CECIL COUNTY 



that they contain very minute quantities of lime and phosphoric acid. 
Where sufficiently deep to retain moisture for the growing plants, 
if supplied with manures they are found to be as productive as many 
soils which have never been called barren. 

The following table gives the mechanical analyses of a typical soil 
and subsoil of the Conowingo barrens: 



MECHANICAL ANALYSES OF CONOWINGO BARRENS. 









•a 

a 


a 


© 


o 

+5 
in 


© 
o 


0.1 to 


a 
a 


g 








u 


a 




o 
















■4J 


T— 1 


•a 




a 


o 

© 


o 


No. 


Locality. 


Description. 


a 

c8 to 


5 
> 


c 

CS 

to 
a> • 

sa 

sa 


a 
£ . 

1 

•- 'in 


o 

| 

.a a 


ery fine sa 
0.05 mm. 


O 

o 

■p 
10 

© 

o 


O 

i 

© . 








o 


o 


o 


a 


fe 


> 


ro 


o 








P. ct. 


P. ct. 


P. ct, 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


4244 


Mount Pleasant, tyj 
mile W. 


Yellow loam, to 
1:2 inches. 


3.18 


1.10 


1.64 


1.66 


8.10 


16.24 


53.06 


15.52 


4245 


Subsoil of 4244 


Brown loam, 13 to 
40 inches. 


4.51 


1.10 


1.72 


1.22 


6.34 


15.34 


55.30 


14.20 



CONOWINGO CLAY. 

There are four small areas of Conowingo clay in the northwestern 
part of Cecil county. These areas partially surround the Conowingo 
barrens, and also come in contact with the Cecil clay formation. The 
surface of the country occupied by these small areas is as rough and 
broken as in the formation just described, but it consists of large, 
rounded hills or long, gentle slopes. The greater part of the forma- 
tion is situated from 200 to 540 feet above sea-level. The highest 
point in Cecil county is found in the area of Conowingo clay, just 
southwest of Rock Springs. 

These soils are derived from the decomposition of greenish, ser- 
pentine rock, and are usually of sufficient depth to make good lands. 
A considerable part of the areas is cleared and cultivated the same 
as are the other productive soils of the uplands. The soils are 
brownish and yellowish loams, which are underlain by yellow and 
red siiff clay loams to a depth of 3 or 4 feet. There is a small amount 
of broken rock and quartz on the surface, but the percentage is not 



MARYLAND GEOLOGICAL SURVEY 



239 



greater than the average of the upland soils. They are strong soils, 
which hold moisture and fertilizers well. In many respects they 
resemble the Cecil clay, but the subsoils of these clays are of a 
peculiar shade of red, and the soils are not as productive as the 
Cecil clay. They will produce good crops of tomatoes and corn. 
Wheat, for some reason, will not yield as well as on the Cecil clay 
or Cecil loams, but it is rotated with the other crops. The forests 
consist of a heavy growth of hard wood. 

The following table gives the mechanical analyses of the soil and 
subsoil of the Conowingo clay: 

MECHANICAL ANALYSES OF CONOWINGO CLAY. 



No. 


Locality. 


Description. 


Organic matter, and 
loss. 


Gravel, 2 to 1 mm. 


o 
o 

•d 

a 

ci 

<D . 

sa 
ga 

o 


s 

© 

c 
<s . 

m a 
Ha 

■— lO 
®o 

s 


© 



■w 

IC 
© 

C 
eS 

<u a 
a a 


o 
■p 

o 
13 

a 

ga 

0>© 

> 


Silt, 0.05 to 0.005 mm. 


© 

o 

o 
S 

o 
d 

*! 

* a 
° 


4^48 


East of Pilot 


Red-brown loam, 
to 8 inches. 

Red clay loam, 8 
to 48 inches. 


P. ct. 
3.92 

6.67 


P. ct. 
2.16 

2.42 


P. ct. 

3.64 

3.88 


P. ct. 

2.52 

2.85 


P. Ct. 

6.17 
5.90 


P. Ct. P. Ct. 

9.33 | 50.40 
11.05 30.69 

1 


P. ct. 
22.15 

36.91 


4249 


Subsoil of 4248 



SASSAFRAS LOAM. 



The largest areas of Sassafras loam are found on the Sassafras 
Neck, Middle Neck, and the old historic Bohemia Manor, but there 
are also areas of considerable importance north and northeast of 
Elkton and east of Perryville. This formation, unlike any of the 
preceding, lies entirely within the borders of the Coastal Plain 
country. It occurs in the southern part of the county as broad, 
gently rolling terraces, from 40 to 80 feet above mean tide-level. In 
the central portion of the county the formation occurs as sloping 
terraces, which rise from 40 to 240 feet above tide-level. In many 
places these terraces are level, with almost no difference in elevation 
for miles. This is especially the case in the neighborhood of War- 
wick, on Sassafras Neck. Here the country seems to present the 



240 THE SOILS OF CECIL COUNTY 

perfectly level condition of the old sea-floor as it must have appeared 
when it first emerged from the sea. 

The drainage has become established to some extent, and, although 
there are some small undrained places, the greater part of the larger 
areas is well drained. Examples of poor drainage on the river necks 
covered by this formation are shown in the small, circular, pond-like 
areas, seldom of more than a few acres in extent. In dry weather 
these places dry up, but during seasons of considerable rainfall they 
usually contain some water. 

The streams of this formation are usually short and carry a small 
volume of water, for they drain but small areas. In their lower 
courses they have a width altogether disproportionate to their drain- 
age basins. This is supposed to be due to the fact that this section 
of Maryland is gradually sinking, so that the lower parts of these 
small streams may be said to be drowned, and consist of broad 
expanses of water which rise and fall each day with the incoming 
and outgoing tides. 

The soils of this formation are derived from the weathering of the 
beds of loam, which are characteristic of certain portions of the 
Pleistocene. These deposits were laid down in comparatively quiet 
waters, and since their deposition have undergone but little change. 
The uniformity of the soils is evidence of the widely extended con- 
ditions of deposition over the sea-floor. The soils consist of from 
8 to 10 inches of light-yellow loam. It is mellow and light, free 
from stone and gravel, and therefore easy to cultivate, and is under- 
lain by yellow loam usually heavier in texture than the soil. The 
subsoils often have a depth of several feet. They are always at 
least 36 inches in depth, and they generally grade into beds of 
gravel and sand. 

These soils are fertile and productive, and can be brought to a 
high state of cultivation. Generally, they are naturally well-drained, 
but in some of the more level portions of the uplands they are 
swampy, and would be much benefited by thorough underdrainage. 
The country around Warwick, on Sassafras ISTeck, is inclined to be 
swampy, especially in wet seasons. Although these soils are uni- 



MARYLAND GEOLOGICAL SURVEY. 



Cecil County, plate xxii. 




FlQ. 1.— FARM-LANDS, ELK NECK. 




FIG. 2.— farm-lands, sassafras neck. 



AGRICULTURAL VIEWS IN CECIL COUNTY 



MARYLAND GEOLOGICAL SURVEY 



241 



form, and can be easily recognized, there are some localities where 
they are slightly lighter in texture, but their generally loamy, mellow 
nature is noticed wherever the formation occurs. These soils have 
for a long time been cultivated, and on certain portions of the for- 
mation many prosperous farms are located. In other portions the 
farms are largely in the hands of tenants, and although the soils are 
productive, the general condition of these places is somewhat run 
down and neglected. 

In good years from 20 to 25 bushels of wheat per acie can be 
raised, but in poorer years 12 to 15 bushels are considered an average 
crop. Corn will produce from 40 to 60 bushels per acre, about the 
same yield as the Cecil loam. Oats will yield from 40 to 50 bushels 
per acre, and good crops of clover and timothy hay are also raised. 
Tomatoes are grown in small quantities with success on these soils. 

The following table gives the mechanical analyses of the soils and 
subsoils: 



MECHANICAL ANALYSES OF SASSAFRAS LOAM. 









T3 




1C 




,_, 


o 


a 










a 

OS 


a 


o 


lO 


o 
o 


— 1 
O 


a 


§ 








u 

0) 


a 


+j 


o 

•a 




a 


8 


o 
o 


No. 


Locality. 


Description. 


as 

a 

o 

Is 

SaOO 
O 


o 

N 

> 

OS 
u 


a 
a 

<s . 

sa 
ga 

o 


Medium san 
0.25 mm. 


Fine sand, 
mm. 


Very fine sa 
0-05 mm. 


o 
o 

+2 
ira 
o 
o 
-w 

50 


Hi 

1 

o 

o 








P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. Ct. 


P. ct. 


4040 


Cecilton, 3 miles SE.. 




4.13 


0.77 


1.61 


2.07 


4.07 


17.73 


63.43 


7.10 


4034 


Bohemia Bridge, Vfa 
miles S. 




3.42 


4.44 


7.97 


4.12 


4.65 


16.08 


50.57 


8.68 


4038 


Concord, ^ mile N. . . 


to 10 inches . ... 


2.70 


1.13 


2.38 


1.75 


7.53 


21.19 


52.77 


10.25 


4041 


Subsoil of 4040 


10 to 30 inches .... 


2.78 




1.04 


1.40 


2.55 


19.19 


60.35 


12.22 


4035 


Subsoil of 4034 


12 to 30 inches — 


2.57 


7.97 


13.97 


5 37 


5.31 


12.81 


3833 


13.33 


4039 


Subsoil of 4038 


10 to 30 inches.... 


2.70 


Tr. 


2.17 


1.30 


4.72 


17.11 


55.22 


15.80 



NORFOLK SAND. 



The largest continuous area of Norfolk sand is just south of 
Elkton, the county seat, and north of Chesapeake City. In addi- 
tion to this large area the formation occurs as a fringe, varying in 
width from one-fourth of a mile to slightly more than 2 miles, border- 
ing all of the deeply indented river necks of the southeastern part of 

16 



242 THE SOILS OF CECIL COUNTY 

Cecil county. The larger areas occur as a rolling upland, from 20 to 
80 feet above sea-level, but where it forms a border around the river 
necks it extends from the shore-line to an elevation of 140 feet. 
Generally, it consists of sloping terraces, but there may be well- 
marked rises from a lower to a higher terrace. There are no un- 
drained areas in this formation, but it often surrounds large marshy 
places along the broad river and Bay shore-lines. 

The Norfolk sand is derived from sandy and gravelly beds of the 
Pleistocene. These materials were deposited in comparatively shal- 
low waters by changing currents, which were strong enough to carry 
coarse grades of sand and occasional beds of gravel. These soils con- 
sist of reddish and brown sands, from 8 to 12 inches in depth, over- 
lying subsoils which consist of sands of a reddish or yellow color. 
The subsoils contain much less organic matter than the soils, and the 
sand is generally more compact. Often there may be a trace of well- 
rounded quartz gravel on the surface, varying from 1 to 6 inches in 
diameter. On the steeper slopes around the outer margin of the up- 
land of the broad terraces there is often a belt or zone where large 
rounded gravel and bowlders come to the surface, but outcroppings 
of this nature are seldom noticed on the more gentle slopes. The 
occurrence of gravel and bowlders is more prominent on the steeper 
slopes around the margin of Sassafras Neck. Gravel beds underlie 
the Norfolk sand soils, and thus insure their perfect drainage. 

These soils have never been brought to a high state of cultivation, 
and the region covered by them is not very prosperous. They sup- 
port a native forest growth, consisting principally of oaks and chest- 
nuts. The same crops are cultivated on these soils which are grown 
on the heavier and more productive soils, and the comparison of the 
respective yields of the two classes is not favorable to the sandy soils. 
On account of their light, sandy nature, they are not adapted to rais- 
ing wheat and grass, and these crops are grown with almost invariably 
poor results. Corn does better, but the yields do not compare favor- 
ably with the better class of lands in this part of the county. If 
crops more adapted to a light, porous soil were grown, much better 
results could be expected. Almost any truck crop or small fruit 



MARYLAND GEOLOGICAL SURVEY 243 

would succeed. Growing peaches for market would doubtless prove 
much more profitable than the raising of wheat and corn with the 
present low yields and low value. The lands between Elkton and 
Chesapeake City are in a much poorer condition than might be ex- 
pected, when the capabilities of these soils for growing special crops 
are considered. 

SUSQUEHANNA GRAVEL. 

The Susquehanna gravel also ranks as one of the large soil forma- 
tions of Cecil county, occupying large areas in the northeast district 
and the greater part of Elk Neck. In the central portion the forma- 
tion occurs as a series of large hills, situated along the junction of the 
Coastal Plain formations with the rolling uplands of the Piedmont 
Plateau. Elk Neck, or more properly speaking, that portion occu- 
pied by the Susquehanna gravel, consists of a continuous chain of 
steep, rounded gravel hills. The entire surface of the formation is 
quite rough and hilly, with here and there a long slope, which breaks 
the monotony of steep hills and narrow valleys. On Elk Neck the 
hills rise from 200 to 300 feet above the Bay. In the central portion 
of the county the elevations are somewhat greater, some of the hills 
rising considerably over 400 feet above mean tide-level. 

The soils are derived from the gravel beds of several different geo- 
logic formations. These deposits were laid down by swift currents of 
water during recent geological times and have undergone little subse- 
quent alteration or change. The soil A 7 aries somewhat in its compo- 
sition, but always contains a high percentage of large, well-rounded, 
quartz gravel, which ranges from one-half to several inches in diame- 
ter. To a depth of 8 inches the soil is a gravel loam, beneath which 
the graA'el content increases to such a great extent that it is almost 
impossible to penetrate farther with a soil auger. Often the under- 
lying gravel beds are very compact and partially cemented together 
by a red ferruginous cement. In many places on Elk Neck the sur- 
face is thickly strewn with great blocks or bowlders of these ferru- 
ginous conglomerates, many of which are several feet in length. In 
the central part of the county the gravels may be deeply stained with 



244 



THE SOILS OP CECIL COUNTY 



iron rust, while in adjoining localities they may be bleached perfectly 
white. The thickness of these gravel beds varies considerably in 
different parts of the formation, frequently exceeding 10 feet in 
depth. Along the northern border of the formation the gravels are 
mere superficial deposits scattered over the residual soils of the Pied- 
mont Plateau. These gravels were probably once much thicker, but 
erosion since their deposition has carried them away until now they 
are thickly scattered over the surface of the rounded hills and slopes 
of the upland. 

The texture of typical samples of the Susquehanna gravel soils can 
be seen in the following table: 



MECHANICAL ANALYSES OF SUSQUEHANNA GRAVEL. 
[Fine earth. 1 









-a 
a 

OS 


S 


d 



m 


d 
o 




d 


a 
a 


Q 

O 








■~ 


s 


+j 


o 






ia 


O 








G 


~ 


•a 


li3 
0-1 


B 


8 


o 


No. 


Locality. 


Description. 


S 
o 

03 CO 

fecc 





•a 

a 


a 


o 


do 


o 










i 

03 

u 


05 

00 


w S 

»6 


a 
a 

05 B 

SB 


a) a 

B 3 

03 a 


+3 

© 
d 


8 

d 

o*a 








O 


Cs 


o 


s 


ft 


> 


on 


o 








P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


4242 


Woodlawn, 1 mile W. 


Gravelly loam, 
to 14 inches. 


5.16 


7.58 


11.58 


15.99 


9.70 


11.99 


30.32 


7.37 


4241 


Principio, 3 miles S.. 


Gravelly loam, 10 
to 26 inches. 


2.53 


5.07 


8.88 


15-68 


24.28 


11.89 


14.68 


16.92 


4243 


Subsoil of 4242 


Red gravelly 
loam. 14 to 36 
inches. 


4.31 


422 


4.32 


8 63 


8.12 


11.85 


41.95 


17.27 



The productiveness of this soil formation also varies greatly, de- 
pending on the materials mixed with gravel. On Elk ISFeck and on 
the larger hills in the northeast district the gravel is mixed with 
coarse sands and is well-nigh worthless for farming purposes. These 
lands have always been held in low esteem, and but few if any at- 
tempts have been made to cultivate them. They are covered with 
a thick but small growth of oaks and chestnuts. In many places a 
small part of the timber is burned for charcoal and, when the iron- 
ore mines were in operation many years ago, the charcoal industry 
was of considerable importance. These gravels compact into excel- 
lent roads. One may ride for miles in the poorer sections of this for- 



MARYLAND GEOLOGICAL SURVEY 215 

mation without seeing any attempt at cultivation, and the general 
appearance of the country is desolate in the extreme. 

In the northern part of the area, along its border, where the cover- 
ing of the gravels is not so deep and where the underlying materials 
form a combination more favorable for the agriculturist the country 
assumes a more prosperous aspect, and many well-improved farms are 
to be seen within the limits of this formation. Here it is possible for 
the plow to mix with the gravel the residual products of the under- 
lying granites and gneisses, and, although still containing a large 
amount of gravel, the soil is stronger and more productive. A larger 
timber growth is noticed, and crops that compare favorably with the 
better class of soils of the county are harvested each year. It fre- 
quently happens, even in the poorest, hilliest regions of this forma- 
tion, that on the long slopes the gravel may overlie a clay which, when 
mixed with the soil, is fairly productive. There is no doubt that 
these soils will produce well by applying manure to them, but not 
such fine crops will be secured as are grown on heavier soils. Crops 
of wheat yielding 10 bushels per acre are sometimes obtained on 
fields where the soils seem almost worthless gravel. In some places 
good yields of corn are obtained, and tomatoes grow rapidly and 
abundantly, being cultivated extensively in some parts of the area. 

ELKTON CLAY. 

There are several well-defined areas of this formation along the 
eastern part of the central portion of the county, the principal ones 
being located near Elkton and southwest of Chesapeake City. This 
formation often occurs as well-marked terraces on portions of some 
of the broad rolling river necks of the lower part of the county. 
These terraces vary in elevation above tide-level from 20 to 180 feet. 
Elkton is situated along the southern margin of one of the broad, 
flat terraces which rises only a few feet above mean tide-level. Often 
these areas are low and poorly drained, and they are therefore wet 
and swampy much of the year. 

The soil consists of from 8 to 10 inches of soft loam, which is often 
grayish in color, sometimes whitish, but the most common colors are 



246 THE SOILS OF CECIL COUNTY 

brown and yellow. The soil is not unlike that of the Sassafras loam. 
The subsoil has a depth of 16 inches, consisting of a yellow light clay 
loam, which is underlain by a mottled clay loam or clay to a depth of 
at least 36 inches. This subsoil is of various colors — drab, yellow, 
red and pink, all mixed together, best described by the term mottled 
clay. As this clay is very compact the natural drainage of the soil 
through such material is by no means good. When this soil occupies 
a place where the natural conditions are conducive to good drainage 
the soils are productive and yield good crops of wheat, corn and grass, 
as well as oats, potatoes and tomatoes, but where the formation occu- 
pies areas with little opportunity for natural drainage it makes an 
undesirable soil for general farming purposes. These soils are apt 
to be cold and wet late in the spring on account of the compact 
nature of the clay subsoils. They bake hard in dry seasons, and it is 
difficult to keep them in good condition at any period of the growing 
season. The wet, poorly-drained land on the north of Grays Hill is 
just such an area. About Elkton and on many other occurrences of 
this formation are fine farm-lands, where good crops are harvested as 
a general rule. Many dairy farms are situated on these soils. In 
some few areas a slight trace of white quartz gravel is scattered on 
the surface, but this is only in exceptional occurrences. Southwest 
of Chesapeake City are some areas with a thick, heavy growth of oak 
and pine, but this does not represent the original timber. 

SUSQUEHANNA CLAY. 

Susquehanna clay, with the possible exception of the Conowingo 
barrens, is probably the most unproductive soil formation found in 
Cecil county. The principal area is several miles in extent in the 
neighborhood of Charlestown, at the head of Northeast Eiver. There 
are other areas surrounding some of the hills on Elk Neck and a 
small, typical area surrounds the western part of Grays Hill, oust 
of Elkton. The surface generally consists of eroded, even terraces 
or long deep slopes around the larger hills of Susquehanna gravel. 
The formation is often found at an elevation of a few feet, but it 
sold 'Xcoods 200 fWt. 



MARYLAND GEOLOGICAL SURVEY 247 

This formation is composed of some of the older Coastal Plain 
series of deposits, which are capped by a slight covering of late Plio- 
cene and early Pleistocene gravels. The soils of this formation are 
derived mainly from the series of stiff, impervious clays, for many 
years grouped under the head of the Potomac formation. Although 
the stiff clays are capped by a slight covering of gravelly loam, they 
are sufficiently near the surface to give character to the soils. The 
capping on. the more level portions consists of from 6 to 10 inches of 
loose gravel loam. On the slopes and on places where washing is 
more pronounced the covering of gravel may be removed and the 
refractory clays are exposed at the surface. Whether or not the 
gravel is present, the soil of the Susquehanna clay is distinctive and 
the condition of the country extremely desolate. 

Pew attempts have been made at cultivating these soils, and these 
have generally been unsuccessful. The soil is usually considered too 
worthless to pay the cost of clearing, and the few attempts made at 
cultivation have proved decidedly discouraging to the farmer. In 
some localities small fields of corn and wheat were observed, but the 
yields are small and the stubborn clays difficult to get in condition. 
Wherever this clay is without a gravel covering it is so stiff that it is 
plowed with the greatest difficulty. Generally clay soils are consid- 
ered productive, but these prove a notable exception. They are 
almost impervious to water, and it has been remarked x that so slowly 
does the water move through them that the growing plant will suffer 
for want of moisture in the midst of plenty. 

The timber growth of these soils is characteristic and distinct from 
that of the Susquehanna gravel, with which this formation nearly 
always comes in contact. Pine and oak constitute the growth, and 
the line of demarcation between the Susquehanna gravel and the 
present formation is well shown by the presence of the pine on the 
Susquehanna clay. The growth is thick, forming pine thickets rather 
than heavy forests. The Pennsylvania and the Baltimore and Ohio 
railroads pass through areas of this formation, the poverty of which 

1 Maryland Experiment Station, Bui. 21. 



248 



THE SOILS OF CECIL COUNTY 



is always remarked, much to the detriment of this section of Mary- 
land, as the impoverished condition of this formation is wrongly sup- 
posed to be indicative of a much larger section of the State. 

The texture of a number of samples of the Susquehanna clay for- 
mation is given in the following table: 

MECHANICAL ANALYSES OF SUSQUEHANNA CLAY. 



No. 



Locality. 



Description. 



4025 
4028 
4023 
4026 



Plum Point, 1 3 4 miles Stiff red clay, to 
NW. i 8 inches. 

Leslie Stiff yellow clay, 

4 to 36 inches. 
Plum Point, 1% miles Stiff red clay 

NW (road cut). 

Subsoil of 4025 Red clay. 8 to 36 

inches. 



P. ct. 
4.15 

4.33 

4.28 
4.78 



IO 


O 


1— 1 


o 


•u 


o 




m 


o 


•ki 


o 








IO 




■a 




•6 


c 


o 




a . 




en 

1) . 




a 






roes 



.5 a 



P. ct. P. ct. 
Tr. J 0.64 

0.78 1.84 



.75 



P. ct. 

0.27 

1.70 

Tr. 

.31 



P. ct. 

2.77 



ga 



P. Ct. 

12.86 






P. ct. P. ct. 

36.87 42.26 



5.66 11.43 39.61 34.95 
2.12 I 17.42 40.13 36.20 
2.00 I 9.20 31.27 51.39 



THE CLIMATE OF CECIL COUNTY 

BY 

OLIVER L. FASSIG 



Introduction. 



Cecil county, the extreme northeast section of the State of Mary- 
land, lies within two distinct physiographic provinces: The northern 
portion, from the mouth of the Susquehanna river eastward to the 
Delaware line and northward to the Pennsylvania line falls within 
the eastern division of the Piedmont Plateau Province. Its surface 
is mostly gently undulating, with a general elevation of about 300 
feet, but rising in places to 450 or 500 feet. The southern portion 
lies within the Coastal Plain Province. By way of Elk and Sassafras 
rivers and other estuaries of the Chesapeake, tide waters are carried 
to nearly every portion of this area. The general level of this 
southern portion is about 50 feet, while its greatest elevations seldom 
exceed 200 feet. Systematic observations of weather conditions re- 
ceived attention at a comparatively early date in Cecil county, but 
the earlier records are of short duration. At intervals in 1843 and 
1844 observations were made by Mr. F. Pinch at Elkton at four 
stated hours daily, namely, at sunrise, 9 A. M., 3 P. M., and 9 P. M., 
probably under the direction of the Franklin Institute of Philadel- 
phia. Soon after the organization of the Smithsonian Institution in 
1847 many stations were established throughout the United States 
for the study of climatic conditions. The records show that observa- 
tions were made under the direction of this Institution at Port De- 
posit, during the months of June and July, 1850, the observer being- 
Mr. Henry W. Thorpe. In 1865 a second station was established at 
Woodlawn by Mr. James O. McCormick, to whom we are indebted 
for the most complete record of the weather made within the limits 



250 THE CLIMATE OF CECIL COUNTY 

of Ceci] county. The record was maintained without interruption 
for nearly eleven years, from March, 1865, to December, 1875, and 
forms the basis of the present discussion of the climatic conditions 
of the county. Observations were regularly made at 7 A. M., 2 
P. M. and 9 P. M., the hours uniformly adopted by the Smithsonian 
Institution, and include a record of temperature, atmospheric pres- 
sure, rainfall, humidity, the direction and force of the wind, the 
state of the weather, and the notation of special features, such as 
thunderstorms, high winds, optical phenomena, frosts, etc. Wood- 
lawn is situated about three miles to the east, and somewhat north, 
of Port Deposit, longitude 76° 4' west of Greenwich, and north 
latitude 39° 38', with an elevation of 465 feet above sea-level. The 
location of Woodlawn gives it a climate which is fairly representative 
of the Piedmont Plateau region of Cecil county. In April, 1897, a 
station was established by the Maryland State Weather Service at 
Port Deposit in connection with the Jacob Tome Institute. The obser- 
vations were made by Mr. A. L. Lamb, from April to July, 1897, and 
by Mr. J. P. France, from September, 1897, to December, 1899, in 
accordance with the plans of the Maryland State Weather Service 
and the United States Weather Bureau, and include a record of tem- 
perature at 8 A. M. and 8 P. M., the maximum and minimum tem- 
peratures of the day, rainfall, snowfall, prevailing direction of the 
wind, state of the weather, and special phenomena. This record is 
incomplete, owing to the lack of observations during midsummer. 

The average monthly and annual values for temperature, rainfall 
and snowfall, deduced from the Woodlawn observations for eleven 
years, as well as the extreme values, are given in detail in the accom- 
panying tallies and diagrams. The original records of observations 
are in the office of the United States Weather Bureau at Washington, 
D. C, all the meteorological records of the Smithsonian Institution 
having been placed in the custody of the National Weather Bureau 
in 1891. 

Temperature Conditions. 

The Woodlawn observations offer a favorable opportunity for the 
study of variation in temperature conditions. Ordinarily a period of 



MARYLAND GEOLOGICAL SURVEY 



251 



ten years does not include within its limits the extremes of tempera- 
ture to which an area having the geographic position of Cecil county 



<Ja/? fe/> Afarrfpr Mtogr. </&/?#(/{//& /f&& &p &£ /Vw Oec. 


faff'- 

so' 

80 
7d 

6<f 

40' 
fa; 

30 
ft 

zd 
/o'- 
er 

-w°- 
























r 
/oo° 

90' 
80° 

70° 

■60' 

SO' 

40° 
raj 

IbJ. 

■30' 

<CJ 

ZO' 
■j0° 
0' 
-JO° 








































































































V 
















// 




s 


\\ 
















/// 


/ 


















































\\ 






















Y 






















' 

















































































































































































































































































Fig. 12. 

(a) Highest monthly mean temperature. 

(b) Normal monthly mean temperature. 

(c) Lowest monthly mean temperature. 

Woodlawn, Cecil County. 



is subjected. It is an interesting fact, however, that the period from 
1865 to 1875 includes a variety of conditions of heat and cold scarcely 



252 



THE CLIMATE OF CECIL COUNTY 



exceeded in a period of over 80 years, as shown by the Baltimore 
observations since 1817. 



da/7 /&£ /for fyr Afotfc/vj7£xA//y./fotf.Sty 0c//Yo/.0ac. 


zoo 
do' 

70"- 

fa.) 

60'- 

a>). 

JO°- 

40'- 

jo'- 

20 

'd 

0°- 
























r 
/Off' 

SO' 

so' 

70' 
60' 

ft; 
■SO' 

-40' 

JO' 

20' 

■/O' 

(C) 

■0' 
(<D 

-/O' 












/ 


\ 








































/ 






















































\ 


\ 






















\ 






















V 




/ 


















\ 














s 








\ 




















































1 






















1 






















// 






















/ 


























































\ 






















\\ 






















y ^ 




/ 






















/ 




















/ 






















<VJ 



























Fig. 13. 

(a) Absolute maximum temperature. 
(6) Average maximum temperature, 
(c) Average minimum temperature. 
Ul) Absolute minimum temperature. 
Woodlawn, Cecil County. 

NORMAL TEMPERATURES AND DEPARTURES THEREFROM. 

Accepting the average temperature at Woodlawn for eleven years 
as a normal for northern Cecil coimtv, we have for this value 51.9° 



MARYLAND GEOLOGICAL SURVEY 



253 



Fahrenheit, or 3.5° less than the normal for Baltimore and vicinity. 
The average annual temperature has varied from this figure between 
the limits of 51.1° and 49.7°, the former value representing the ex- 
tremely warm year of 1865 and the latter the exceptionally cold year 
of 1875. The average temperature for the year considered in itself 
affords but an inadequate idea of the true character of the conditions 
of heat and cold of a given locality. The value 51.9° may be derived 



TABLE I. 

MEAN MONTHLY AND ANNUAL TEMPERATURE, 

WOODLAWN, CECIL COUNTY, MARYLAND FROM 1865 TO 1875. 

Latitude 39° 38' North ; Longitude 76° 4' West of Greenwich, Elevation 460 feet. 



Year. 


Jan. Feb. 


Mar. Apr. 


1 
May June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Ann'l 




1865 


30.5 


32.4 


45.9 


54.8 


61.8 


73.5 


74.2 


71.6 


70.6 


52.5 


44.7 


36.4 


54.1 


1865 


1866 


29.4 


32.8 


40.3 


54.0 


60.1 


70.7 


76.9 


69.2 


66.7 


55.5 


46.1 


32.4 


52.8 


1866 


1867 


23.8 38.2 


36.2 


52.4 


58.0 


70.7 


74.2 


72.5 


66.3 


55.0 


45.2 


28.8 


51.8 


1867 


1868 


26.5 24.1 


39.0 


45.6 


57.3 


69.6 


78.8 


73.8 


65.5 


51.5 


43.3 


29.1 


50.3 


1868 


1869. . . . 


35.2 35.4 


36.9 


51.6 


58.9 


70.8 


73.7 


72.2 


65.6 


47.9 


38.0 


34.4 


51.7 


1869 


1870 


37.7 


31.6 


35.4 


50.9 


62.3 


72.4 


77.2 


74.2 


65.9 


56.2 


43.5 


32.8 


53.3 


1870 


1871..... 


29.1 


31.1 


45.3 


55.8 


63.0 


71.2 


73.4 


75.1 


60.1 


56.0 


39.7 


28.2 


52.3 


1871 


1872. ... 


28.2 


30.1 


31.4 


52.0 


64.6 


73.4 


79.4 


75.2 


67.3 


52.8 


38.6 


26.3 


51.6 


1872 


1873 


27.4 


28.8 


35.8 


48.6 


60.0 


71.2 


77.2 


72.0 


65.3 


53.6 


36.8 


37.1 


51.2 


1873 


1874 


35.5 ; 32.9 


39.7 


42.8 


61.5 


73.6 


74.5 


70.3 


66.5 


54.4 


42.0 


34.4 


52.3 


1874 


1875., 


24.9 23.1 


34.5 


45.4 


63.4 


71.3 


74.5 


71.2 


63.4 


52.4 


39.5 


33.0 


49.7 


1875 


Average 


29.8 


31.0 


38.2 


50.4 61.0 


71.7 


75.8 


72.5 


65.7 


53.4 


41.6 


32.1 


51.9 


Average. 



from mean monthly values which differ widely from one another, 
representing a variable climate, or it may be composed of monthly 
values approximately equal, representing an equable climate. In 
Cecil county the average January temperature is 29.8° and the 
average July temperature 75.8°, showing a difference of 45° between 
the coldest and warmest months of the year when normal conditions 
prevail. The difference becomes still greater when the coldest and 
warmest months of extreme seasons are contrasted. For example, 
February, 1875, was but 23.1°, while the average temperature of 
July, 1872, was 79.4°, showing an extreme difference in monthly 



254 



THE CLIMATE OF CECIL COUNTY 



average values of 56.3°. Such contrasts in seasonal temperatures 
increase in magnitude in the temperate regions as the distance from 
the coast increases and reach their greatest development in northern- 
central regions of the large continental masses. The month exhibit- 
ing the greatest amount of change in the average temperature from 
rear to year is February, with a maximum of 38.2° in 1867 and a 
minimum of 23.1° in 1875, a difference of 15.1°. The least change- 
able month is June, having varied but 4° within the period of eleven 
years. The variability of temperature during the winter months is 
nearly three times as great as during the summer months. The 
monthly and annual mean temperatures for the entire period from 
1865 to 1875 are shown in Table I on the preceding page. 



EXTREMES OF TEMPERATURE. 

In selecting a suitable locality for residence or for conducting 
profitable farming operations it is of vital importance to know the 
extreme limits of variability in temperature to which the region is 
subjected, as well as the time and manner of occurrence of changes. 
An intimate knowledge of the extreme daily or monthly range, of 
the probability of occasional sudden changes of great magnitude, of 
the occurrence of frost at critical periods of plant growth, is of the 
utmost importance. Average values are not a sufficient guide. The 
difference between the highest and lowest temperatures of the month 
and year under extreme conditions and under average conditions is 
shown by the following figures: 



fe 



a 



>> be 

H3 < 



Z V. 



Difference with ex- ) 
treme conditions., \ 

Difference with av- ) 
erage conditions. . . J" 



7-1 
53.0 



80 80 

54.0 52.0 



66 54 
45.7 43.2 



42 
34.4 



42 40 
31.031.7 



51 
42.1 



57 02 74 110 
4::. 045. 040. 4 93.0 



From this table it appears that the annual extremes of temperature 
may vary by 110°, that the monthly extremes in February and 
March may vary by 80°, while the summer months exhibit a varia- 
bility of about one-half that of the winter months. Julv is the month 



MARYLAND GEOLOGICAL SURVEY 



255 



HIGHEST OBSERVED TEMPERATURES, 
WOODLAWN, CECIL COUNTY, MARYLAND, FROM 1865 TO 1875. 



Year. 


Jan. Feb. Mar. Apr. 


May 


June 


July 


Aug. 


Sept. Oct. 


Nov. 


Dec. 


Ann' 1 




1865 

1866 

1867 

1868 

1869 

1870 

1871 

1873 

1873 

1874 

1875 


54 

46 
56 
63 
63 
60 
54 
60 
60 
49 


58 
58 
53 
64 
58 
65 
54 
54 
76 
52 


70 
73 
66 
80 
70 
61 
70 
64 
57 
64 
60 


76 
80 
70 
73 
80 
84 
88 
88 
70 
62 
68 


80 
82 
90 

78 
93 
85 
88 
90 
87 
89 
83 


90 
90 
89 
91 
90 
94 
88 
91 

94 
93 


94 
97 
93 
100 
94 
95 
90 
96 
94 
90 
90 


90 
86 
90 
90 
94 
90 
88 
92 
90 
93 
85 


91 83 

88 80 

87 85 
90 74 

88 74 
83 78 
82 78 

92 76 
90 74 
90 ! 74 

89 i 74 


78 
69 
72 
72 
62 
69 
66 
58 
63 
70 
68 


68 
68 
54 
51 
56 
60 
52 
48 
70 
59 
43 


94 
97 
93 
100 
94 
95 
90 
92 
94 
94 
92 


1865 
1866 

1867 
1868 
1869 

1870 
1871 
1872 
1873 
1874 
1875 




56.3 


59.1 


66.8 


76.3 


85.7 


90.9 


93.9 


89.8 


88.1 77.3 


67.9 


57.2 


94.1 


Average 
Maximum. 



TABLE III. 

LOWEST OBSERVED TEMPERATURES, 
WOODLAWN, CECIL COUNTY, MARYLAND, FROM 1865 TO 1875. 



Year. 


Jan. 


Feb. 


Mar. 


Apr. 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Ann'l 




1865 






20 


40 


43 


60 


62 


56 


49 


34 


33 


11 


11 


1865 


1866 


—7 


4 


19 


35 


42 


59 


63 


55 


48 


36 


25 


4 


-7 


1866 


1867 


3 


13 


20 


38 


38 


52 


61 


60 


43 


38 


17 


6 


3 


1867 


1868 


8 


-1 





35 


44 


56 


65 


63 


44 


30 


30 


10 


-1 


1868 


1869 


14 


14 


10 


30 


40 


52 


58 


57 


44 


38 


24 


12 


10 


•1869 


1870 


13 


7 


20 


31 


47 


58 


58 


58 


49 


36 


24 


6 


6 


1870 


1871 


5 


2 


39 


36 


46 


60 


60 


60 


41 


33 


22 


-4 


-4 


1871 


1872 


2 


6 


o 


32 


44 


56 


70 


58 


50 


36 


13 


1 


1 


1872 


1873 


-10 


—2 


2 


35 


42 




66 


60 


44 


33 


16 


16 


-10 


1873 


1874 


8 


12 


19 


23 


42 


55 


65 


54 


50 


33 


20 


10 


8 


1874 


1875 


-5 


-4 


15 


22 


40 


57 


64 


58 


44 


33 


31 


14 


—5 


1875 


3.3 


5.1 


14.3 


31.5 


42.5 


56.5 


62.9 


58.1 


46.0 


33.4 


22.3 


7.8 


1.1 


Average 
Minimum. 



256 



THE CLIMATE OF CECIL COUNTY 



during which the highest temperatures of the year are most probable. 
During the period from 1865 to 1875 a temperature of 100° was 
recorded only once at Woodlawn, namely, on July 11 and 15, 1868. 
This record was probably exceeded by two or three degrees in July, 
1900, as a reading of 103° was reported by Professor A. F. Galbreath 
at Darlington, Harford county, but a few miles distant. Tempera- 
tures of 90° and above occur almost annually during the months of 
June, July and August, frequently in September, and occasionally in 
May. The lowest temperature of the year is most likely to occur in 



TABLE IV. 

AVERAGE DAILY, MONTHLY AND ANNUAL RANGE, AND ABSOLUTE MONTHLY AND 
ANNUAL RANGE OF TEMPERATURE. 



Based upon observations at Woodlawn 


, Cecil County, Maryland. 






Authority. 


Jan. 


Feb. 


Mar. 


Apr. 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Aun'l 


Average 2 P. M. 


























observations. 


37.0 


38.7 


45.8 


58.5 


68.2 


79.2 


83.7 


80.2 


74.3 


62.1 


50.0 


38.1 


59.6 


Average 7 A. M. 




























observations. 


26.1 


26.8 


33.6 


47.0 


57.2 


68.9 


73.4 


69.6 


61.8 


48.8 


37.2 


27.9 


48.2 


Average daily 




























range. 


10.9 


11.9 


12.2 


11.5 


11.0 


10.3 


10.3 


10.6 


12.5 


13.3 


12.8 


10.2 


11.4 


Average 




























maximum. 


56.3 


59.1 


66.8 


76.3 


85.7 


90.9 


93.9 


89.8 


88.1 


77.3 


67.9 


57.2 


94.1 


Average 




























minimum. 


3.3 


5.1 


14.2 


30.6 


42.5 


56.5 


62.9 


58.1 


46.0 


33.4 


22.3 


7.8 


1.1 


Average monthly 




























range. 


53.2 


54.0 


52.6 


45.7 


43.2 


34.4 


31.0 


31.7 


42.1 


43.9 


45.6 


49.4 


93.0 


Absolute monthly 




























maximum. 


62 


76 


80 


88 


92 


94 


100 


94 


92 


85 


78 


70 


100 


Absolute monthly 




























minimum. 


-10 


-4 





22 


38 


52 


58 


54 


41 


28 


16 


-4 


-10 


Absolute range. 


72 


80 


80 


66 


54 


42 


42 


40 


51 


57 


62 


74 


110 



January, although it frequently occurs in the early part of February. 
The coldest day between 1865 and 1875 occurred in January of 1873 
with a minimum of 10° below zero. This record was probably low- 
ered by one or two degrees during the intense cold of February 10 
to 13, 1899, when nearly all records of extreme cold within the State 
of Maryland were lowered. The average minimum temperature for 
the month of January is 3.3°, and of February 5.1°. The month 
of April, with a probable minimum of 30.6°, and with the possibility 
of a temperature as low as 22°, is subject to heavy frosts as late as 
the 15th of the month. In the fall the first heavy frost is likely to 
occur about the middle of October. The period of five months from 



MARYLAND GEOLOGICAL SURVEY 



257 



May to September is practically free from injurious frosts, while the 
period of safe plant growth may be extended to six months by adding 
the last two weeks of April and the first two weeks of October. The 
mean daily range in temperature, i. e. the difference between the 
highest and the lowest recorded temperature from day to day during 
the year is about 18°, and varies from about 21° in August to about 
14° in January. The greatest daily range may vary from 43°, as 
in August of 1900, to 29°, as in January, 1897. The following 
figures are based upon Professor Galbreath's record at Darlington, 
Harford county: 







Apr. 

May 


a 
3 

1-5 


>> 

3 


si 

3 
< 


+i 

a 
to 


o 
O 


> 
o 

55 


6 
© 
O 

37 
16 




Average daily range. ... 14 


36 I 34 
17 17 


38 
20 


39 
20 


34 
20 


36 
18 


43 

21 


32 
19 


41 
19 


37 

16 


43 

18 



Rainfall. 

Precipitation in Cecil county is abundant and under normal condi- 
tions is quite evenly distributed throughout the year. This is charac- 
teristic of the Atlantic Coast states. The average annual amount, 
including rainfall and melted snow and all forms of precipitation, is 
48 inches. The following figures show the amount of fall in each 
month expressed in inches and hundredths of an inch, and as a per- 
centage of the total fall for the year: 



Normal precipitation 

Percentage of total 

fall for the year 



3.09 



'!} 



S3 

ft 

3.65 

8 


s 

4.21 

9 


p. 

< 


g 

4.29 
9 


s 
i-s 

3.92 

8 


>> 

3 
i-s 

4.33 
9 


bi 
3 
< 


3. 
© 


O 

O 


> 

o 

3.97 

8 


6 

© 

R 

3.00 

6 


3.73 

8 


5.74 

12 


4.01 
9 


3.91 

8 



47.85 
100 



The monthly amounts vary from three inches in January and Decem- 
ber, the months of least precipitation, to nearly six inches in August, 
the month of greatest rainfall. These figures may vary greatly from 
month to month in any given year, but long periods of excessively 

dry weather are rare. Precipitation is most uniform in amount in 
17 



258 



THE CLIMATE OF CECIL COUNTY 



December and January. From 1S65 to 1875 there was not a single 
instance in which there was a fall of less than one inch in the months 
of January and February. While the average precipitation for a 
series of years is fairly uniform, great variability may be exhibited in 
individual cases. Rainfall is the most variable of all climatic factors. 



fer/w 


Jas? 


feb 


Afar 


dpr 


May 


l/(//7£ 


</(//(/ 


rf</<7 


\5ep 


06/ 


/toy 


tec. 


lafes 


■/z 
/o 

8 

6 

fa) 

4 

®- 
Z 

0. 


























12. 
/o 
8. 

#/ 

4 

0J 

2 

tVJ 
























































































































































































































































1 1 


































































l/?Cfr£S 


c/a/F 


fej> 


/for 


rfpr 


flay 


Ja/% 


Jr/a 


4oy 


Jep 


06/ 


My 


M 


{r, />", 



Fig. 14. 

(a) Maximum monthly precipitation. 

(b) Average monthly precipitation. 

(c) Minimum monthly precipitation. 

Woodlawn, Cecil County. 
(Rainfall and melted snow expressed in inches and tenths of an inch. 



This is strikingly exhibited in the following table of maximum and 
minimum amounts recorded at \Yoodlawn during eleven years: 



Maximum amounts.. 
Minimum amounts. . 
Range 



4.97 
1.00 
3.97 



5.86 
0.89 
4.97 



7.33 
1 . 63 

5.70 



- - 



>> be 



8.457.569.358.74 LI. 83 8.987.71 8.42 
1 .801.070.41 1.39 1.131.07 0.36 2.24 
6.656.498 94 7.3510.68 7.91 7.356.18 



6.00 54.45 
1.21 35.50 
4.79 18.95 



It is shown by the above figures: (1) that abundant precipitation is 
likely to occur in all months of the year; (2) that the summer months 
are likely to show a greater variability in amount than the winter 



MARYLAND GEOLOGICAL SURVEY 259 

months, both the greatest and the least amounts occurring in the warm 
months; (3) that all months of the crop season are liable at times to 
have an insufficient rainfall for the requirements of successful crop 
growth; (4) that a period of more than four or five weeks without 
rainfall is extremely improbable. In the eleven years from 1865 to 
1875 there was no calender month without some rainfall. At times 
the monthly amounts have been very small, as was the case in June, 
1873, when but 0.41 inch was recorded, but the months of small 
rainfall have almost invariably been preceded or followed by months 
of abundant rains. This may be seen in the following table, in which 
the minimum amounts of rainfall during the growing season for 
eleven years are given, together with the amounts recorded in the 
months immediately preceding and following: 



Amount of Rainfall 


Minimum Rainfall. 


Amount of Rainfall 


in preceding month. 


Date. 


Amounts. 


in succeeding month, 


5.86 


inches 


March 


, 1866 


1.63 inches 


4.75 i 


inches. 


7.33 


ii 


April, 


1871 


1.80 " 


2.67 


" 


2.10 


" 


May, 


1875 


1.07 " 


4.70 


" 


6.61 


« 


June, 


1873 


0.41 " 


2.90 


u 


4.23 


(< 


July, 


IS 72 


1.39 " 


7.22 


" 


5.70 


t( 


Aug., 


1869 


1.18 


3.04 


cc 


1.51 


a 


Sept., 


1865 


1.07 " 


4.01 


it 


5.26 


» 


Oct., 


1874 


0.36 « 


2.50 


[£ 



The smallest rainfall within any month during this period occurred 
in October, 1874, when but 0.36 inch fell, but there was a heavy 
fall in the preceding month, namely, 5.26 inches, and the dry spell 
occurred toward the close of the growing season. In June, 1873, 
there was but 0.41 inch, but this was likewise preceded by abundant 
rains in May, amounting to 6.61 inches, a sufficient quantity, when 
stored up in the ground, to supply moisture to crops for a considerable 
period. Further details of precipitation may be learned by consult- 
ing the accompanying Table V. 



!60 



THE CLIMATE OF CECIL COUNTY 



TOTAL MONTHLY AND ANNUAL PRECIPITATION, 
(Rain and melted snow, In inches and hundredths of an inch.) 

WOODLAWN, CECIL COUNTY, MARYLAND, FROM 1865 TO 1875. 



Sept. 


Oct. 


Nov. 


Dec. 


1.07 


4.01 


2.82 


6 00 


8.08 


4.65 


2.75 


2.92 


1.41 


4.30 


2.32 


2.41 


8.13 


2.10 


8.42 


3.61 


3.04 


4.79 


4.18 


6.00 


3.56 


4.56 


2.24 


1.84 


2.55 


3.65 


5.00 


1.56 


2.70 


4.30 


3.60 


2.42 


4.50 


7.71 


4.00 


1.21 


5.26 


0.36 


2.50 


1.85 


2.95 


2.60 


5.83 


3.21 


4.01 


3.91 


3.97 


3.00 


8.98 


7.71 


8.42 


6.00 


1.07 


0.36 


2.24 


1.21 



1865 
1866 

1867 
1S6S 
1869 
1870 
1871 
1872 

1ST:! 4.97 

1874 3.06 

1875 



3.83 

'.Mil 
1.00 
4.07 
4.26 
4.10 
2.20 
1.07 



2. 78 
3.09 
4.97 
1.00 



5.53 
5.86 

3.85 
2.87 
5.13 
3.44 
2.14 
0.89 
3.94 
3.83 
2.66 
3.65 
5.86 
0.89 



6.10 
1.63 
6.35 
3.00 
5.47 
3.21 
7.33 
2.97 
3.10 
1.84 
5.27 
4.21 
7.33 
1.63 



4.75 
2.78 
4.16 
1.94 
6.05 
1.80 
2.60 
3.55 
S.45 
2.10 
3.73 
8.45 
1.80 



&. .;> 

3.96 
T.56 
5.30 
5.08 
5.06 
2.67 
2.11 
6.61 
2.07 
1.07 
4.29 
7.56 
1.07 



4.93 
9.35 
3.74 
2.37 
2.35 
5.81 
4.10 
4.23 
0.41 
1.17 
4.70 
3.92 
9.35 
0.41 



6.96 

2.90 
3.31 

4.78 



1.51 
3.60 
11.38 
3.00 



5.70 1.13 



4.17 
3.77 
1.39 
2.90 
8.74 
2.98 
4.33 
8.74 
1.39 



3.83 
4.61 
7.22 

11.55 
3.46 

11.81 
5.74 

11.81 
1.13 



51.39 
53.96 

50.41 
51.81 

49.07 
47.87 
41.38 
35.50 
54.45 
42.511 
47.96 



1865 
1866 
1867 
1868 
1869 
1870 
1871 
1872 
1873 
1874 
1875 



17. 85 Average. 
54.45 Greatest. 
35.50 Least. 



Snowfall. 

The snowfall record extends over a period of about ten years, from 
1866 to 1875. The average annual amount is 31.7 inches The 
amount has varied from 22 inches in 1866 to 57 inches in 1867. The 
season of snowfall extends from November to April. There wa- no 
snowfall during half of the above period in November and during 
more than half the period in April. The monthly distribution is 
shown in the following; table: 





■r. 


« 

9.3 

16.0 

1.0 


'.» . 8 
2 7 . 8 


u 
P. 
< 

1 .1 
5 5 


S 


- 

a 

-. 


>> 

3 
1-5 


bis 

3 
< 


C. 
C 


+5 

O 


> 

O 

0.9 
•2.7 
0.0 


•J 
- 

6.8 

11.5 
O.l 


s 
- 
1* 




0.1 








::4 7 
















5 7 4 














22 . :; 



The heaviest snowfall during this period, as shown by the above 
figures, occurred in the month of March, 27. S indies having been 



MARYLAND GEOLOGICAL SURVEY 



261 



recorded in 1867 and 27.5 inches in 1869. The snowfall of Feb- 
ruary, 1899, exceeded these amounts. There is no record for this 
month at "Woodlawn, but the observer at Port Deposit reported 34 
inches, occurring as follows: February 7, 1899, 1.5 inches; 8th, 3.5 
inches; 13th, 14 inches; 14th, 12 inches. In the accompanying table 
the amount of snowfall occurring during each month from 1865 to 
1875 is shown. 

TABLE VI. 

MONTHLY AND ANNUAL DEPTH OF SNOWFALL, 
(Measured in Inches and tenths of an inch.) 

WOODLAWN, CECIL COUNTY, MARYLAND, FROM 1865 TO 1875. 



Year. 

1865 

1866 

1867 

1868 

1869 

1870 

1871 

1872 

1873 

1874 

1875 



Jan. 


Feb. 


Mar. 


- 


- 





12.0 


1.0 


2.1 


10.4 


7.6 


27.8 


8.4 


15.4 


14.5 


0.1 


4.6 


27.5 


1.0 


9.4 


5.5 


12.5 


10.6 


2.0 


4.3 


4.0 


11.0 


12.0 


14.8 


1.5 


4.5 


16.0 


2.2 


- 


- 


13.6 


7.2 


9.3 


9.8 


12.5 


16.0 


27.8 


1871 


1874 


1867 


0.1 


1.0 


1.5 


1869 


1866 


1873 








5.5 


3.5 






3.2 



1.1 
5.5 
1868 





June 



July 



Aug. 


Sept. 


Oct. 


Nov. 











0.8 























0.1 











1.5 











2.6 



































2.7 











2.1 



































0.9 

2.7 
1872 




Dec. 



11.2 
7.2 

11.5 
5.2 

6.8 
5.5 
5.2 

10.2 
5.3 
0.1 
7.0 
6.8 

11.5 

1867 
0.1 

1874 



22.3 

57.4 
38.5 
41.6 
24.9 
31.3 
34.2 
35.7 
26.0 

34.7 
57.4 
1867 
22.3 
1866 



1865 
1866 
1867 
1868 
1869 
1870 
1871 
1872 
1873 
1874 
1875 
Average. 

Greatest 
Amounts. 

Time of 

Occurr'uce 

Least 
Amounts. 

Time of 

Occurr'nce 



THE HYDROGRAPHY OF CECIL COUNTY 

BY 

H. A. PRESSEY 



Cecil is the northeast county of Maryland, bordering on the states 
of Pennsylvania and Delaware. Chesapeake Bay, with its numerous 
arms projecting into the county, forms the southwestern boundary, 
while the Susquehanna flowing from Pennsylvania separates Cecil 
and Harford counties, forming the boundary line between them for a 
distance of 25 miles. On the south, forming the county line, is the 
Sassafras river, which may be considered more of an estuary or arm 
of Chesapeake Bay, than a river. The topography of the county is 
flat, there being few points with an elevation of 400 feet above the 
sea. The rivers are short, usually not over 20 miles in length, and 
are correspondingly small in discharge. Sassafras river at the south- 
ern border is tidal for the greater part of its length. It is broad, but 
has but small discharge owing to the limited size of its drainage area. 

Elk River, another arm of Chesapeake Bay, is fed by Little Elk 
and Big Elk creeks, both of which rise in Pennsylvania, and drain 
the northwestern portion of Cecil county. Great Northeast Creek 
also rising in Pennsylvania, drains the northcentral portion of the 
county and empties into Northeast River. These streams are all of 
much the same character, draining a rolling farming country. 

Larger than any of these is Octoraro Creek. This creek rises in 
Lancaster county, in southeast Pennsylvania, and flows in a south- 
westerly direction between Lancaster and Chester counties into Mary- 
land, where it empties into the Susquehanna about 5 miles below the 
State line and 2 miles above Port Deposit. The drainage area is 
more rugged than for streams farther south in Cecil county. A study 
of the flow of this stream has been made by the U. S. Geological Sur- 



264 THE HYDROGRAPHY OF CECIL COUNTY 

vey, in conjunction with the Maryland Geological Survey, and sys- 
tematic measurements have been made at Rowlandsville. Meas- 
urements of flow have been made with a small Price current 
meter at regular intervals according to the customary methods of the 
Survey. A gage of some kind is established by which the height of 
the river can be determined and recorded daily, or several times a day. 
This gage reads to the nearest tenth, so that for each day of the year 
the stage of the river is known. 

Frequent measurements are made by the hydrographer of the flow, 
usually at some bridge across the stream. Careful soundings are 
made, so that the area of the cross-section can be computed. This 
cross-section is then divided into smaller sections of 5 or 10 feet in 
width by marks upon the guard-rail of the bridge. By knowing the 
width and average depth it is possible to compute the area of each of 
the partial sections, and the velocity in each can be determined with 
the current meter. 

This instrument, designed on the principles of the propeller of a 
ship, is suspended from the bridge in the water and held perfectly 
quiet. The flowing water turns the propeller wheel, its speed being 
dependent upon the velocity of the water. The number of revolu- 
tions in a certain short period of time is noted by the hydrographer. 
Each revolution is recorded by a small electric buzzer, through which 
a current is passed when the revolving wheel of the current meter 
makes each revolution. The hydrographer, watch in hand, counts 
the number of breaks in the current by the sounds of the buzzer and 
records it in his note book. Usually a run of 50 seconds is made for 
convenience in computation, and each run is repeated as a check. 
Electric recorders have been used for this purpose, but it has been 
found that better results can be obtained by the use of the buzzer. 

Before using the meter in the field it is rated, so that the relation 
between the velocity of the current and the number of revolutions of 
the wheel is known. This rating is done at Washington by passing 
the meter through still water at various known speeds and noting the 
number of turns made by the wheel in a distance of 100 feet. The 
results of a number of such runs are plotted on cross-section paper, 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XXIII. 




FIG. 1.— BOHEMIA RIVER, WITH THIN FRINGE OF SHORE-TIMBER 




Fig. 2.— little elk creek, with river birch and sycamore. 



HYDROGRAPHY OF CECIL COUNTY. 



MARYLAND GEOLOGICAL SURVEY 265 

the revolutions per second being plotted as abscissae, and the velocities 
per second as ordinates. A smooth curve is then drawn through these 
points, and any desired intermediate velocities can then be interpo- 
lated. A rating table is then constructed, taking the data from this 
curve. 

When the measurement of a stream is made and the number of 
revolutions of the wheel noted, the velocity of the flow can be deter- 
mined at once by reference to this table. Knowing the velocity in 
each of the smaller sections across the stream, and the area of each, 
the quantity of water passing can be found by multiplying the two 
together, and the total flow past the station is found by the summa- 
tion of the flow through all partial areas. ' In this way the actual flow 
of the river can be found on various days. A list of measurements 
made in this way of the Octoraro is given on one of the following 
pages. 

Owing to the expense of making such measurements it is not prac- 
ticable to make them every day in the year on the same stream, and 
yet it is important that the flow of the stream for each day in the 
year should be known. To this end the river height is read each day 
on the gage as described above. By knowing this reading at the 
time of each measurement made with the meter, the relation between 
the gage height and the discharge of the stream is determined. A 
station rating curve is drawn with gage height as abscissae, and dis- 
charges in cubic feet per second as ordinates. 

The result of each measurement is plotted on cross-section paper 
and a smooth curve drawn through these points. From this curve 
the approximate discharge in cubic feet per second can be read at 
once for any assumed gage height, so that with the gage height known 
the approximate discharge can be determined for each day in the 
year. Computations of this kind have been made on Octoraro Creek. 
The results are given below in condensed form, showing the maxi- 
mum, minimum and mean discharges for each month, with the run- 
off in second-feet per square mile, and depth in inches on the water- 
shed. The record of the gage heights is also given, and the station 
rating table. 



266 THE HYDROGRAPHY OF CECIL COUNTY 

OCTORARO CREEK. 

Measurements were made at the wagon bridge in the village of 
Rowlandsville. There was no place at this station for fastening a 
permanent gage rod on account of the danger of being carried away 
by floods, so that as in the case of many such stations a wire gage 
was suspended from the bridge with a sash weight at the lower end, 
which could be lowered to the water surface and afterwards raised 
nearly to the bridge floor, so that it would not be disturbed by high 
waters. A scale board 14 feet long, painted white and graduated 
with small nails to feet and tenths of feet, was fastened to the floor 
timber of the bridge in such a way that when the weight was raised 
the height could be read directly from the position of the index on 
the graduated scale board. 

The initial point for making soundings was at the end of the hand- 
rail on the lower side of the bridge from the left bank of the stream. 
A bench mark was established and verified with Wye level. It con- 
sists of a cross cut in the top of capstone on the lower side of bridge 
abutment on the left bank of the stream, and is 17.67 feet above the 
datum of the gage. A great many measurements of discharge were 
made at this station by Mr. E. G. Paul and Mr. Hugh TV. Caldwell, 
the first measurement being made [November 21, 1896, and the regular 
record of gage heights was begun on that day. In October, 1899, 
however, the records were stopped, so that computations here given 
extended only through the month of September, 1899. 

The following tables give the daily records for the periods during 
which the observations were made. 



MARYLAND GEOLOGICAL SURVEY 



267 



Estimated Monthly Discharge of Octobako Creek at Rowlandsville, Md. 
(Drainage area 217 square miles.) 



1896 

January 

February 

March 

April 

May 

June 

July 

August 

September.. . . 

October 

Nov. 22 to 30. 

December. . . . 

The year. 



DISCHARGED IN SECOND-FEET. 



Maximum. Minimum 



540 
225 



145 
145 



192 
158 



TOTAL IN 

ACRE-FEET 



3,427 
9,715 



RUN-OFF. 



Second-feet 
per sq. mile. 



0.89 
0.73 



Depth in 
inches. 



. 29 
0.84 



1897 

January 

February 

March 

April 


2,580 

6, 150 

500 

2,002 
920 

1,270 
520 
960 
170 
170 

1,845 
S20 


155 
170 
170 
170 
170 
145 
135 
130 
130 
130 
155 
185 


329 
1,021 
230 
370 
321 
222 
192 
186 
136 
141 
298 
275 


20,230 
56,705 
14,142 
22,017 
19,737 
13,210 
11,805 
11,437 
8,092 
8,670 
17,730 
16,909 


1 . 52 

4.71 
1.06 
1.71 
1.48 
1.02 
0.88 
0.86 
0.63 
0.65 
1.37 
1.27 


1.75 
4.90 
1 . 22 
1.91 


May 


1.71 


June 


1.14 


July 


1.01 


August 

September .... 

December .... 


0.99 
0.70 
0.75 
1.53 
1.46 


Tbe year. . . . 


6,150 


130 


310 


220,684 


1.43 


19.07 


1898 

February 

March 

April 

May 

June 


705 
985 
985 
535 

1,070 
562 
375 

1,687 
480 
375 

1,605 

3,320 


220 
220 
245 
245 
300 
220 
200 
200 
ISO 
200 
220 
245 


306 
325 
315 
322 
523 
282 
230 
415 
243 
225 
650 

951 

— 399 


18,815 
18,050 
19,369 
19,160 
32,158 
16,780 
14,142 
25,518 
14,459 
13,835 
38,677 
58,475 


1.41 
1 . 50 
1.45 
1.48 
2.41 
1.30 
1.06 
1.91 
1.12 
1.04 
3.00 
4.38 


1.57 
1.56 
1.67 
1.65 

2 . 78 
1.45 


July 


1 22 


August 

September .... 

November 

December. 


2.20 
1.25 
1.20 
3.34 
5.06 


The year. . . 


3,320 


180 


289,438 


1.84 


24.95 


1899 


1,470 

1,952 

2,087 

960 

525 

345 

345 

960 

1,470 


225 
325 
285 
345 
305 
185 
130 
120 
102 


642 
822 
763 
508 
388 
254 
188 
181 
262 


39,475 
45,652 
46,915 
30,228 
23,857 
15,114 
11,560 
11,129 
15,590 


2.96 

3.79 
3.52 

2.34 
1 . 79 
1.17 
0.87 
0.83 
1.21 


3.41 
3.95 
4.06 

2.61 




2.06 


August 


1 . 31 
1.00 
0.95 
1.35 


The year. . . . 













268 



THE HYDROGRAPHY OF CECIL COUNTY 





Daily Gage Height of Octoraro Creek, Rowlandsville, 


Md., for 1897. 


a 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


3.10 


3.20 


:;.4:» 


3.30 


3.40 


3.40 


3.00 


3.40 


2.80 


2.80 


3.10 


3.30 


•> 


3.10 


3.20 


:f.t;n 


3.30 


3.40 


3.40 


3.00 


3.30 


2. so 


2.80 


6.00 


3.40 


3 


3.10 


l.SII 


3.50 


3.30 


3.110 


3.40 


3.00 


3.30 


2.80 


2.80 


4.15 


3.45 


4 


3.10 


3 55 


3.50 


3.30 


3.50 


3.40 


3.00 


3.30 


2.SO 


2.80 


3.70 


3.(10 


5 


3.10 


3.45 


3.50 


3.30 


3.40 


5.45 


3.00 


3.30 


2.80 


2. so 


3.40 


4.35 


6 


3.10 


8.68 


3.45 


3.30 


3.30 


3.70 


2.90 


3.20 


2.80 


2. so 


3.40 


3.70 


7 


3.10 


10.10 


3.40 


3.30 


3.30 


3.70 


2.90 


3.20 


2.80 


2.80 


3.30 


3.45 


8 


3.10 


9.20 


3.40 


3.30 


3.30 


3.45 


2.90 


3.20 


2.80 


2.80 


3.(15 


3.30 


9 


3.10 


7.50 


3.30 


4.60 


3.20 


3.40 


2.90 


3.30 


2. SO 


2.80 


3.50 


3.30 


10 


3.10 


5.40 


3.30 


5.50 


3.20 


3.30 


2.90 


3.30 


2.80 


2.80 


3.60 


3.30 


11 


3.10 


3.50 


3.30 


6.15 


3.20 


3.30 


2.90 


5.10 


2.80 


2.90 


3.70 


3.60 


12 


3.10 


3.a5 


3.20 


5 . 65 


3.20 


3.30 


2.90 


3.40 


2.80 


2.85 


3.45 


3.40 


13 


3.10 


3.30 


3.20 


4.55 


4.85 


3.30 


2.90 


3.30 


2.80 


2.80 


3.35 


3.30 


14 


3.10 


3.30 


3.20 


3.85 


5.00 


3.20 


2.90 


3.20 


2.80 


2.80 


3.30 


4.65 


15 


3.10 


3.40 


3.20 


3.60 


5.00 


3.20 


2.90 


3.10 


2.80 


2.80 


3.20 


4.90 


Hi 


3.10 


4.55 


3.20 


3.50 


3.75 


3.20 


2.90 


3.10 


2.80 


2.80 


3.20 


3.95 


17 


3.10 


4.05 


3.20 


3.50 


3. 55 


3.20 


2.90 


3.10 


3.05 


2.80 


3.20 


3.70 


is 


3. in 


3.55 


3.40 


3.45 


3.40 


3.20 


2.90 


3.00 


2.90 


2.80 


3.30 


3.60 


19 


3.10 


3.60 


4.15 


3.45 


3.30 


3.20 


3.10 


2.90 


2.90 


2.90 


3.30 


3.60 


20 


3.10 


3.40 


3.60 


3.40 


3.30 


3.20 


3.10 


2.90 


2.90 


2.90 


3.30 


3.50 


21 


6.70 


3.45 


3.40 


3.30 


3.40 


3.20 


3.75 


3.05 


2.80 


3. (HI 


3.20 


3.50 


22 


6.65 


3.15 


3.40 


3.30 


3.65 


3.20 


3.S5 


3.05 


2.80 


3.05 


3.20 


3.40 


83 


4.45 


6.00 


3.40 


3.20 


3.40 


3.10 


3.55 


3.00 


3.20 


3.20 


3.20 


3.30 


84 


3.30 


3. SO 


4.20 


3.20 


3.40 


3.10 


3.40 


3.00 


3.20 


3.20 


3.80 


3.30 


25 


3.20 


3.45 


3.95 


3.20 


5-05 


3.10 


3.30 


3.00 


3.10 


3.20 


3.20 


3.30 


26 


3.20 


3.35 


3.55 


3.20 


4.80 


3.10 


3.30 


3.00 


3.00 


3.20 


3.20 


3.35 


27 


3.20 


3.40 


3.40 


3.20 


3.90 


3.10 


4.25 


2.90 


3.00 


3.20 


4.85 


3.50 


88 


3.20 


3.40 


3.30 


3.20 


3.50 


3.10 


3.95 


2.90 


3.00 


3.10 


4.10 


3.50 


29 


3.80 




3.30 


3.20 


3.40 


3.00 


3.65 


2.80 


2.90 


3.10 


3.65 


3.50 


30 


3.20 




3.30 


3.20 


3.40 


3.00 


3.50 


2. SO 


2.80 


3.00 


3.40 


3.40 


31 


3.20 




3.30 




3.40 




3.40 


2.80 




3.00 




3.50 



Daily Gage Heigiit of Octoraro Creek, Rowlandsville, Md., for 18'J8. 



1 


3.40 


3.70 


3.60 


4.10 


3.90 


3.90 


3.40 


3.30 


3.30 


3.40 


3.40 


4.60 


•> 


3.HO 


3.70 


3.60 


4.00 


3. so 


3. SO 


3.30 


3.30 


3.30 


3.40 


4.75 


4.60 


3 


3. 60 


3.70 


3.(10 


3.9(1 


3.80 


3.80 


3.30 


3.40 


3.30 


3.40 


4.55 


4.50 


4 


3.50 


3.75 


3.(1(1 


3.80 


3.70 


3.70 


3.80 


5.85 


3.30 


3.40 


4 . 55 


4.75 


5 


3.45 


3.70 


3.50 


3.80 


3.75 


3.70 


3.70 


4.911 


3.30 


3.40 


5 . 55 


9.'.'5 


(1 


3.40 


3.70 


3.50 


3.80 


3.80 


3.70 


3.50 


4.35 


3.30 


3.40 


4.90 


S.40 


7 


3.40 


3.60 


3.50 


3.70 


4.25 


3.70 


3.40 


3.95 


3.45 


3.30 


4.50 


6.70 


8 


3.40 


3.(15 


3.50 


3.70 


4.30 


3.60 


3.40 


3.85 


3.90 


3.30 


4.05 


5.90 


9 


3.40 


3.(15 


3.50 


3.70 


4.05 


3. till 


3.40 


4.00 


3.50 


3.30 


3.90 


5.3(1 


10 


3.40 


3.(15 


3.50 


3.60 


3.80 


3.60 


3.30 


4.50 


3.50 


3.30 


3.75 


4.911 


11 


3.40 


3.(10 


3.50 


3.60 


3.85 


3.50 


3.30 


3.45 


3.50 


3.40 


3.60 


3.(15 


12 


3.55 


3.50 


3.50 


3.(10 


4.25 


3.50 


3.30 


3. SO 


3.40 


3.40 


3.50 


3.(10 


13 


1.30 


3.50 


3.50 


3.60 


1.10 


3.50 


3.30 


3.70 


3.40 


3.40 


3.85 


3.60 


14 


3.(10 


3.50 


3.. Ml 


3.50 


4.10 


3.511 


3.30 


3.55 


3.40 


3.40 


3.65 


3.60 


15 


4.40 


3.50 


3.50 


3.50 


1.25 


3.50 


3.30 


3.50 


3.30 


3.40 


3. till 


3.50 



I. till 

3.S5 
3.45 
3.40 
3.75 



3.50 
3.40 

3. 15 
3.90 
5.10 



3.50 

3.50 

3.50 

3.50 
3.50 



3.50 

3.50 
3.50 
3.50 
3.50 



5.00 
5.85 

4.95 

I..V, 
4.85 



3.50 
3.50 
3.50 

3.50 
4.35 



3.3 1 
3.30 
3.30 
3.55 

3.55 



3.(10 
3.70 
4.50 
4.25 
3.80 



3.30 

3.30 
3.30 
3.30 
3.20 



3.30 
3.30 

3.30 
3.30 
3.30 



3.(10 
4.70 
4.90 
6.20 
5.70 



3.50 
3.50 

3.50 

3.90 
9.05 



3.85 

3.50 
(.30 

3.80 
3.65 



4.(10 
3.95 

3.80 
3. so 
3.70 



3.50 

3.(1(1 
3. SO 
4.10 
5.111 



3.50 
3.511 
4.30 
1.10 
3.90 



1. 91 1 
4.50 
4.25 
1.20 
1.35 



3.75 

3.70 
3.70 

3.(111 
3.(10 



3.35 
3.3K 
3.30 
3 311 
3.30 



3.50 
3.50 
3.50 
3.50 
6.35 



3.211 
3.20 
4.10 
3. SO 
3.60 



3.95 
3.(15 

3.50 

3.10 
3.40 



5. 15 
I.9.", 
4.(15 
4.70 
1.3;", 



7. SO 
11.05 

6.76 

4.35 

4.30 



1.00 

3. ',11 
3.:,5 
3.50 
3 .Ml 

:; 60 



3.70 
3.(10 
3.60 



3.80 

3.70 
3.70 
3.75 

1.(15 
1.311 



4.05 
1.15 
1.IKI 
l.llll 
3. '.HI 



4.10 
4.. so 
1.05 
l.llll 
3. '.HI 
3.90 



3.(111 
3.511 
3.. Ml 
3. 15 
3.10 



3.30 

3.311 
3.95 
3.85 
3. I.', 
3 '.(I 



3.85 

3.70 

3.(10 
3.45 
3.30 

3 311 



3.40 
4.20 
3.90 

3.55 

3.15 



3.111 
3.35 
3. till 
3.55 
3.50 
3.10 



till 
4.90 
1 . 75 

1.80 

4.70 



4.80 

4.10 

4.00 

1. 00 

3.9(1 
1.1.-, 



MARYLAND GEOLOGICAL SURVEY 



269 



The accompanying diagrams (Figs. 15-17) represent graphically 
the variations in discharge during 1897-1899 which are given in 
detail in the foregoing tables. From these figures it is readily seen 
that the average flow of the Octoraro past Rowlandsville is rarely 
more than 500 cubic feet per second, except during December or the 
first months of the year when the melting of the snow and the 
spring rains swell the stream to nearly twice that discharge. The 
diagrams also show that the rises in the water are rapid and that 
the fall in the water occurs within the next succeeding clay or two 
unless there are lone; continued rains. 



Sec.-ft. 

12,000 

11,000 

10,000 

9,000 

8,000 

7,000 

6,000 

5,000 

4,000 

3,000 

2,000 

1,000 





JAN. 
10 20 


FEB 

10 20 


MARCH 
10 20 


APRIL 
10 20 


MAY 
10 20 


JUNE 
10 20 


JULY 
10 20 


AUG 
10 20 


SSPT 
10 20 


OCT 
10 20 


NOV 
10 20 


DEC 
,,10 20 
















































































































































































































































































































































































































































































































































































































































































































































































1 




| 




















i 










































L 




1 








jL 






1 


1 


[ 












■L 


















a 




i 





Fig. 15. Discharge of Octoraro Creek at Rowlandsville, 1897. 



270 



THE HYDROGRAPHY OF CECIL COUNTY 





JAN. 
10 20 


FEB. 
10 20 


MARCH 
10 20 


APRIL 
10 20 


MAY 
10 20 


JUNE 
10 20 


JULY 
10 20 


AUG. 

10 20 


SEPT. 
10 20 


OCT. 
10 20 


NOV. 
10 20 


DEC. 
10 20 


Sec.-ft. 

5,500 




































































5,000 




































































4,500 




































































4,IM)(I 




































































3,500 




































































3,000 




































































2,500 




































































2,000 




































































1,500 




































































1,000 












































I 






















500 




.4 






I 








J| 










i 


Li 
















1 
















r 









A 


L 




Jl 






JL 




L 


JL 


« 


*l 


■iW«WPf ' 


* 1 



Fig. 16. Discharge of Octoraro Creek at Rowlandsville, 1898. 



4000 



3500 



3000 



2500 



J 000 



1500 



1(K»0 



500 



JAN 
10 20 


FEB 
10 20 


MAR. 
10 20 


APR. 
10 20 


MAY 
10 20 


JUNE 
10 20 


JULY 

10 20 


AUG. 
10 20 


SEPT. 
10 20 


OCT. 
10 20 


NOV. 
10 20 


DEC. 

10 20 




























































































































































































































































































































































































































































































































































NC 


F 


n 


r 


F?D 







Fig. 17. Discbarge of Octoraro Creek at Rowlandsville, 1899. 



MARYLAND GEOLOGICAL SURVEY 



271 



Daily Gage Height 


OF OCTORARC 


River at Rowlandsville, Md. 


, FOR 1899. 


eg 
P 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


4.60 


3.90 


4.30 


4.50 


4.00 


3.80 


3.50 


3.35 


3.50 








a 


4.80 


4.00 


4.45 


4.40 


4.00 


3.80 


3.40 


3.30 


3.45 








3 


4.95 


4.00 


4.50 


4.20 


4.00 


3.80 


3.40 


3.25 


3.40 






4 


4.80 


4.30 


4.80 


4.10 


4.00 


3.70 


3.40 


3.30 


3.30 






5 


4.95 


4.40 


7.45 


4.00 


4.00 


3.70 


3.55 


3.30 


3.20 






6 


5.45 


4.40 


6.70 


3.90 j 4.00 


3.70 


3.90 


3.30 3.15 


.... 1 .... 


7 


5.55 


4.30 


5.75 


5.30 1 4.00 


3.60 


3.60 


3.55 J 3.20 






8 


4.80 


4.10 


5.15 


5..05 ! 4.35 


3.75 


3.85 


3.40 3.20 > .... 






9 


4.55 


4.00 


4.50 


4.85 4.35 


3.75 


3.85 


3.35 1 3.i0 






10 


4.50 


3.90 


4.05 


4.75 


4.05 


3.90 


3.55 


5.30 3.40 







11 


4.50 : 3.85 3.80 


4.65 


4.20 


3.75 


3.50 3.55 3.45 




12 


4.30 I 4.20 3.75 


4.30 


4.25 


3.70 


3.45 3.45 


3.70 






13 


4.75 ! 4.85 6.30 


4.30 


4.05 


3.70 


3.45 3.45 


3.50 






14 


4.40 1 5.00 4.60 


4.30 


4.15 


3.70 


3.45 3.40 


3.40 






15 4.30 4.70 5.15 


4.30 


4.00 


3.70 


3.50 3.40 3.40 






16 


4.25 4.65 


4.70 


4.20 1 4.05 


3.70 


3.50 


3.40 3.30 








17 


4.15 7.20 


4.40 


4.25 4.00 


3.65 


3.40 


3.40 3.30 








18 


4.00 ! 6.90 


4.30 


4.20 


4.25 


3.60 


3.55 


3.40 , 3.30 








19 


3.90 ' 6.80 


4.25 


4.20 


4.05 


3.60 


3.45 


3.40 3.35 








20 


3.85 6.45 


4.20 


4.20 


4.00 


3.60 


3.40 


3.30 3.85 


21 


3.70 


6.15 


4.05 


4.20 


4.00 


3.65 


3.35 


3.25 


3.70 






22 


3.70 


5.75 


4.00 


4.20 


3.95 


3.60 


3.35 


3.40 


3.60 






23 


3.60 


5.50 


4.00 


4.20 


3.90 


3.50 


3.30 


3.35 


3.35 






24 


6.30 


5.25 


3.90 


4.10 


3.90 


3.50. 


3.35 


3.30 


3.30 






25 


6.10 


5.05 


5.20 


4.10 


3.85 


3.65 


3.30 


3.30 1 3.50 






26 


5.60 


5.55 


4.70 


4.10 


3.80 


3.65 


3.65 


3.30 


6.30 








27 


4.90 


5.05 


4.50 


4.00 


3.80 


3.50 


3.65 


3.50 


4.95 








28 


4.45 


4.55 


6.95 


4.00 


3.80 


3.50 


3.40 


3.55 


4.65 








29 


4.25 




5.60 


4.00 


3.80 


3.80 


3.40 


3.50 


4.00 








30 


4.10 




5.00 


4.00 


3.85 


3.60 


3.40 


3.50 


4.15 








31 


4.05 




4.80 




3.80 




3.40 


3.50 







List of Discharge Measurements Made on Octoraro Creek at 
Rowlandsville, Md. 



Date. 



1896. 
November 21 

1897. 

January 23 

July 21 

Augustl6 

AugustSl 

September 18 

October 22 

November 2 

November 3 

November 29 

December 15 

1898. 
January 8. 

January 26 

February 12 

February 21 

February 22 

February 23 

March 12 

May 24 

May 28 

June 20 

June 22 

July 5 

July 12 



Meter 
Number. 



Gage heig't 
(feet). 



Area of sec. 
(sq. ft.) 



Mean veloc. 
(ft. per sec.) 



Discharge 

(sec. ft.) 



3.00 



133 



1.03 



138 



25 


3.42 


251 


1.00 


248 


65 


3.45 


270 


0.98 


264 


66 


3.10 


253 


0.69 


175 


66 


2.80 


233 


0.59 


138 


66 


2.90 


222 


0.61 


136 


66 


3.10 


227 


0.60 


138 


66 


6.00 


526 


3.50 


1843 


66 


4.00 


310 


1.43 


444 


66 


3.50 


264 


0.71 


202 


66 


4.70 


363 


1.96 


714 


66 


3.40 


248.5 


0.81 


201 


66 


4.00 


319 


1.35 


430 


66 


3.70 


290 


1.20 


360 


66 


4.90 


404 


2.31 


934 


66 


4.10 


339 


1.23 


428 


96 


3.90 


285 


1.19 


339 


66 


3.60 


309 


0.76 


236 


91 


4.10 


323 


1.28 


416 


91 


3.70 


271 


1.33 


362 


91 


4.30 


344 


1.23 


426 


91 


3.50 


254 


0.83 


214 


91 


4.10 


332 


1.27 


424 


91 


3.30 


258 


0.81 


211 



272 



THE HYDROGRAPHY OF CECIL COUNTY 



List of Discharge Measurements Made on Octoraro Creek at 

ROWLANDSVILLE, Md. . 



1898 

July 19 

Augusts 

August 12 

August25 

September 30 

October 6 

October 17 

October 22 

October 26 

December 7 

December 26 

1899. 

January 24 

February 4 

March 15 

March 31 

April 15 

April 21 

May 8 

May 20 

Juue 5 

June 16... 

Juue28 

June 29 

July 15 

July 28 

August 7 

August 11 

August 19 

August28 

September 25 ... 



Meter 
Number. 



91 
91 
91 
91 
91 
131 
91 
91 
91 
91 
91 



91 
91 
91 
91 
9] 
91 
91 
91 
91 
91 
91 
91 
'.H 
91 
91 
91 
;il 
'.il 
91 



Gage helg't 

(feet). 



3.80 
3.40 
3.80 
6.40 
3.50 
3.60 
3.30 
3.70 
4.10 
6.40 
4.20 



6.40 
4.40 
5.00 
4.80 
4.30 
4.20 
4.50 
4.00 
3.80 
3.70 
3.50 
4.00 
3.50 
3.40 
3.50 
5.20 
3.40 
3.60 
5.60 



Area of sec. 
(sq. ft.) 



Mean veloc. 
(ft. per sec.) 



Discharge 
(sec. ft.) 



303 
255 
300 
564 
255 
207 
258 
306 
328 
534 
344 



542 
351 
390 
372 
340 
329 
354 
326 
271 
259 
24(1 
317 
268 
253 
265 
447 
201 
268 
429 



0.95 
0.88 
0.96 
2.94 
0.82 
0.88 
3.30 
0.93 
1.28 
2.91 
1.23 



2.79 
1.51 
1.70 
1.93 
1.48 
1.42 
1.51 
1.26 
1.22 
0.73 
0.77 
1.22 
0.81 
(1.74 
0.64 
2.33 
0.57 
0.76 
2.60 



225 
289 

1663 
209 
182 
200 
887 
420 

1557 
434 



1505 
531 
666 
722 
507 
470 
538 
413 
333 
189 
185 
3S7 
219 
186 
171 

1044 
144 
206 

1113 



SUSQUEHANNA RIVER. 

Susquehanna river is by far the largest and most important river 
whose waters touch Cecil county. This river rises in Otsego Lake in 
Otsego county, N. Y., at an elevation above the sea of about 1193 
feet. The main stream, with its numerous large tributaries, forms the 
largest river on the Atlantic slope of the United States, forming the 
watershed between waters flowing north and west into the St. Law- 
rence, the Mississippi and Great Lakes and those flowing into the 
Atlantic streams. Its tributaries drain a part of the State of New 
York, about one-half of the State of Pennsylvania and the north- 
eastern portion of Maryland. Its total drainage area, as measured 
by Mr. Henry Gannett, of the TJ. S. Geological Survey, is 27,655 
square miles. Of this amount about 255 square miles are in the 
State of Maryland. The drainage area of the Susquehanna varies 
from a comparatively ilat, though in part somewhat broken, area in 



MARYLAND GEOLOGICAL SURVEY 273 

New York State, to the mountainous regions of central Pennsyl- 
vania, where its tributaries have narrow and precipitous valleys, its 
falling waters and rocky bed giving evidence of the possibility of 
waterpower development in many places along their courses. 

Many waterpowers have been developed on the large tributaries of 
the Susquehanna, but there are several powers possible of develop- 
ment which, were they not located in the midst of the coal regions, 
would have long ago been important for manufacturing purposes. 
The main stream has a uniform declivity while in New York State, 
with a bed of gravel or sand and but few rocky ledges either in the 
bed or banks of the stream, yet with banks moderately high and 
seldom subject to overflow, representing in all respects a typical stream 
of the north-central states. The Susquehanna, in flowing through 
Pennsylvania, takes on more of the character of a mountain stream 
flowing along the base of mountain ranges with high banks, and drift- 
filled bed in which large boulders are frequently found. 

The fall is quite uniform until the junction of the West Branch, 
when rapids and more decided falls become frequent with rocky bed 
and banks at these places. As the Maryland line is approached the 
river valley broadens out, sometimes being nearly a mile in width, 
then narrowing to a few hundred feet. Rocky cliffs rise on either 
side, so that one following down the stream on the immediate bank is 
completely hemmed in by the rock walls. Along this part of its 
course occasional rapids occur, some of which would furnish power 
on a very large scale. Developments, however, on this portion of 
the river would be expensive, owing to the width of the stream and 
the heavy floods which frequently occur. On the other hand the 
bed and banks are of solid rock and favorable for the construction of 
dams. Railroad lines extend along nearly the whole lower course of 
the stream, giving ample transportation but interfering with develop- 
ment on a large scale, as a high dam would flood the tracks in many 
places. 

The following profile of the course of the Susquehanna and its 
tributaries shows the steepness of the beds of the headwaters between 

the source and Williamsport, Pa., and the gentler slopes of the lower 
18 



274 



THE HYDROGRAPHY OF CECIL COUNTY 



courses of the river between TVilliamsport and its mouth at Havre de 
Grace. The latter figure also shows that the total fall of the river 
from the State line, near Bald Friar, to tide-level at Havre de Grace 
is only a little over sixty feet, or an average of about four feet per 
mile. 




Fig. 18. Profile of Susquehanna River from its source to Williamsport, Pa. 




Fig. 10. Profile of Susquehanna River from Williamsport, Pa., to Havre de Grace. 

There are a number of lakes in the basin of the Susquehanna, but 
they are so small in comparison with the immense drainage area of 
the river that they have but little effect upon the regulation of its 
flow. Possibilities of artificial storage are good, as dams of compar- 
atively small cost could be built on some of the upper tributaries and 
large quantities of water stored. A large part of the drainage area 
has been cleared of timber, but in the mountain regions of Pennsyl- 



MARYLAND GEOLOGICAL SURVEY 275 

vania there are still immense tracts of forest lands. At flood height 
the river may rise 30 feet, while the minimum flow of the stream is 
small, as may be seen from the records of discharge on the follow- 
ing pages. 

In the Tenth Census of the United States, volume xvi, may be 
found data upon the fall of the tributaries and main Susquehanna, 
and a record of waterpowers developed and undeveloped. 

A systematic study of the flow of the Susquehanna has been made 
since 1890 by the U. S. Geological Survey, the point of measurement 
being at Harrisburg, Pennsylvania. Observations of the height of 
water in the river were made several years previous at the pump- 
house of the waterworks located in the western part of the city of 
Harrisburg, and these records have been continued to date and fre- 
quent current meter measurements made by hydrographers of the Sur- 
vey. The gage is located in the pump well, which is directly con- 
nected with the river by means of large water mains. A float in this 
well is attached to a cable and counterweight, the height of water 
being indicated upon a painted scale. The datum is the low water 
mark of 1804. Observations are made by the engineer, Mr. C. M. 
Nagle, each morning before starting the pumps. The records have 
been furnished since 1890 through the courtesy of Mr. E. Mather, 
President of the Harrisburg Waterworks Company. 

Measurements of discharge are made by the method previously de- 
scribed, from an open iron bridge on Second Street, the initial point 
of sounding being the iron upright at the east end of the bridge. The 
channel at and below the station is straight for about 2500 feet, the 
banks being high and the current of moderate velocity. The stream at 
this point is divided into two channels with a, large island between, and 
at the time of lowest water it has been found advantageous to meas- 
ure the right-hand channel by wading. The first measurement was 
made on March 30, 1897, by Mr. E. Gr. Paul. The record of gage 
heights and the results of measurements at Harrisburg are here given. 
Also the computation of flow by months. 



276 



THE HYDROGRAPHY OF CECIL COUNTY 



Daily Gage Height, in Feet, of Susquehanna River at Harrisburg, 
Pennsylvania, for 1891. 



a) 
Q 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


2.83 


[0.58 


11.00 


8.25 


3.58 


2.00 


2.75 


3.25 


4.67 


1.75 


2.50 


4.25 


2 


3.00 


11.50 


II. (HI 


;'.(in 


3.50 


1.92 


2.50 


3.17 


4.00 


1.67 


2.50 


4.00 


3 


3.33 


11.50 


7.33 


S.5S 


3.42 


2.00 


2.5s 


3.08 


3.67 


1.67 


2.33 


3.67 


4 


4.50 


11.17 


6.67 


8.75 


3.42 


2.00 


3.17 


2.02 


3.33 


1.58 


2.25 


3.50 


5 


5.25 


Ki. 11 


5.67 


8. 12 


3.25 


2.00 


4. (IS 


3! 00 


3.00 


1.58 


2.25 


J . 58 


6 


5.00 


8.92 


5.67 


S.IMI 


3.08 


2.00 


3.50 


3.08 


3.00 


1.58 


2.25 


S.75 


7 


5.50 


7.67 


5 • 25 


7.17 


3.00 


2.0S 


3.08 


3. (HI 


3.83 


1.58 


2.17 


9.50 


8 


5. +2 


7.50 


5.00 


6.42 


3.00 


2.17 


2.67 


3.33 


4.67 


1.75 


2.17 


S.33 


9 


4.92 


7.50 


4.67 


6. (HI 


2.92 


2.58 


2.75 


3.08 


4.50 


2.5S 


2.00 


7.00 


10 


4.5(1 


7.42 


4.67 


5.67 


2.75 


2.75 


2.67 


2.83 


4. US 


3.00 


2.00 


6.00 


11 


4.08 


7.50 


6.17 


5.33 


2.67 


3.00 


2.02 


2.75 


3.83 


2.83 


2.00 


5.42 


12 


4-25 


7.42 


7.08 


6.08 


2.67 


2.75 


2* S3 


2.5S 


3.5(1 


2.67 


2.67 


5.00 


13 


6.00 


7.00 


8.50 


7.33 


2.58 


2.67 


2.75 


2.58 


3.08 


2.67 


3.67 


4.17 


U 


8.75 


6.42 


9.67 


9.00 


2.50 


2.67 


2-50 


2.5S 


3.00 


2.5S 


4.00 


4.a3 


15 


7.92 


5.92 


10.75 


8.50 


2.50 


2.58 


2.25 


2.5(1 


3.00 


2.42 


4.25 


4.00 


Iti 


7.5(1 


5.58 


10.00 


8.00 


2.42 


2.50 


2.17 


2.50 


2.67 


2 '33 


4. us 


3.83 


17 


6.67 


5.92 


8. S3 


7.67 


2 42 


2 42 


2.00 


2.50 


2.67 


2.08 


3.75 


3.75 


18 


6.00 


14.25 


7.75 


7.42 


2 '33 


8.88 


1.83 


2.42 


2.58 


2.00 


4.00 


3.67 


19 


5.67 


19.00 


6.83 


6.83 


2.25 


2.33 


1.92 


2.25 


2.58 


1.83 


4.83 


4.58 


20 


5.08 


17.83 


6.17 


6.75 


2.25 


2.33 


2.08 


2.42 


2.50 


1.92 


4.75 


5.00 


21 


4.83 


13.25 


5.92 


6.33 


2.04 


3.33 


2.08 


2.25 


2.25 


2.17 


4.67 


4.75 


22 


4.50 


11.75 


6.&3 


5.92 


2.00 


3.58 


2-08 


2.0S 


2.17 


2.50 


4.25 


4.17 


23 


7.08 


11.50 


6.67 


5.50 


2.13 


5.42 


2.00 


2.00 


2.08 


3.25 


4.17 


3.83 


24 


9.17 


10.25 


8.08 


5.17 


2.25 


6.17 


2.00 


3. (IS 


2.08 


4.67 


4.08 


3.92 


25 


9.50 


9 00 


10.33 


5.00 


2.33 


5.58 


4.a3 


6.50 


2.00 


4.17 


5.42 


4.58 


26 


9.42 


8.25 


10.83 


4.75 


2.20 


4.58 


4.00 


6.58 


1.02 


3.67 


6.42 


6.33 


27 


8.42 


11.33 


1(1. (IS 


4.67 


2.25 


4.33 


3.83 


5.25 


1.83 


3.17 


6.17 


8.25 


28 


7.50 


13. OK 


8.92 


4.25 


2.21 


3.75 


3.33 


5.67 


1.75 


3.00 


5.42 


9.33 


29 


7.00 




7. S3 


4. OS 


2.17 


3.50 


3.00 


6.00 


1.75 


2.83 


5.00 


8.58 


30 


7.08 




7.50 


3.83 


2.08 


3.50 


2.75 


5. as 


1.75 


2.67 


4.67 


7.83 


31 


9.83 




7.67 




2.00 




3.92 


5.17 




2.58 




8.50 



Daily Gage Height, in Feet, of Susquehanna River at Harrisburg, 
Pennsylvania, for 1892. 



>> 

<a 
a 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


8.50 


2.83 


4.50 


9.75 


3.00 


5.92 


4.67 


1.92 


2.02 


1.08 


0.50 


1.92 


2 


8.25 


2.92 


4.00 


9.00 


2.83 


5.50 


4.33 


2.00 


2.50 


1.25 


.50 


1.83 


3 


S.75 


2.02 


3.58 


S.50 


2.83 


5.17 


3.75 


1.83 


2.33 


1.42 


.50 


1.75 


4 


9.ai 


3.0S 


3.25 


11.75 


2.83 


7.58 


3.67 


2.00 


2.17 


1.25 


.50 


1.58 


5 


8.83 


3.0S 


3.00 


14.33 


4.50 


12.50 


3.50 


3.00 


2.00 


1.08 


.50 


1.58 


6 


8.00 


3.00 


2.67 


14.67 


5.83 


12.00 


3.58 


2.83 


1.83 


1.08 


.50 


1.50 


7 


7.83 


3.00 


2.83 


13.17 


7. 58 


11.25 


3.42 


2.83 


1.83 


1.00 


.50 


1.50 


8 


6.83 


2.02 


2.83 


11.33 


7.58 


0.00 


3.42 


3. (Ml 


1.75 


1.00 


.50 


1.50 


9 


5.a3 


2.75 


3.83 


0.50 


1 . 83 


7.67 


3.42 


2.67 


1.67 


1.00 


.75 


1.58 


10 


5.67 


2.50 


5.25 


7.83 


6.67 


7.00 


3.00 


2.42 


1.50 


1.00 


.02 


1.67 


11 


4.17 


2.58 


6.17 


7.00 


5.58 


7.12 


2. as 


2.17 


1.50 


1.00 


1.00 


2.42 


12 


3.67 


2.50 


5.92 


6.42 


5.00 


7.00 


2.5(1 


2.08 


1.42 


.92 


1.17 


4.25 


13 


3.75 


2.00 


5.67 


5.67 


4.75 


6.42 


2.17 


".42 


1.42 


.92 


1.17 


4.00 


14 


5.50 


1.08 


5.00 


5.33 


4.25 


5.42 


2.17 


2.50 


1.50 


.83 


1.17 


3.50 


15 


11.83 


1 . 75 


4.42 


4.75 


4.17 


4.67 


2.33 


3.50 


2.33 


.83 


1.25 


3.08 


16 


13.17 


1.83 


4.00 


4.75 


4.17 


4.17 


2.42 


4.17 


2.33 


.83 


1.25 


2.83 


17 


10.83 


1.67 


3.50 


4.33 


-1 . 12 


3.75 


2.42 


4.00 


2.0s 


.83 


1.25 


2.92 


18 


o.os 


1 . 76 


3.33 


4.33 


4.83 


3.58 


2 25 


3.50 


1.83 


.83 


1.25 


2! 67 


10 


7.75 


2.00 


3.08 


1.00 


4.0:.' 


3.50 


2.25 


2.83 


1.67 


.83 


1.02 


2. 58 


20 


7.67 


2.33 


3.00 


3. S3 


5.67 


3.50 


2.08 


2.67 


1.50 


.83 


2.50 


2.50 


21 


7.00 


2.17 


2.9! : 


3.67 


7.25 


3.67 


2.00 


2.33 


1.50 


.83 


2.50 


2.42 


22 


6.17 


2.50 


2.67 


3.50 


8.25 


4.00 


1.75 


2.11 


1.50 


.83 


2.92 


2.08 


23 


5.33 


2.67 


2.50 


3. 12 


S.S3 


3.67 


1.67 


1.02 


1.33 


.83 


3.5s 


1.50 


21 


1.75 


3.17 


2.50 


3.50 


s.75 


3.50 


1 67 


1.83 


1.17 


.83 


3.33 


.92 


25 


1.50 


3.50 


2.67 


3.50 


8.25 


3.67 


1.67 


1.92 


1.11 


.75 


2.02 


1.08 


26 


4.33 


1.33 


3.50 


3. 58 


7.33 


4.17 


1.58 


2.17 


1 . 25 


.58 


2.50 


2.58 


27 


3.58 


4.50 


1.5(1 


3.58 


6.67 


3.58 


1.50 


2. (Ml 


1.25 


.68 


2.08 


2. (HI 


28 


2.50 


1.83 


10.83 


3.50 


6.50 


3.25 


1.50 


2.00 


L.25 


.58 


2.00 


2 . 25 


29 


2.0S 


4.67 


13. (KI 


3.33 


6.33 


3.50 


1.50 


2.00 


1.08 


.58 


2.00 


2.25 


30 


2.83 




12.00 


3.11 


7.08 


1.83 


1 . 12 


2.25 


1.08 


.58 


1.02 


2.25 


31 


2.83 




10.58 




6.42 




1.61 


3.00 




.50 




2.17 



MARYLAND GEOLOGICAL SURVEY 



i^T7 



Daily Gage Height, in Feet, of Susquehanna River at Harrisburg, 
Pennsylvania, for 1893. 



Q 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


2.00 


2.67 


2.58 


6.08 


4.92 


3.67 


2.33 


0.92 


3.58 


2.00 


2.17 


4.00 


2 


2.50 


3.00 


2.58 


6.00 


4.83 


3.67 


2.17 


.83 


4.17 


2.00 


2.17 


3.83 


3 


2.83 


4.00 


2.75 


6.42 


5.50 


3.50 


2.08 


.83 


3.92 


1.83 


2.17 


3.67 


4 


2.83 


4.17 


2.75 


7.50 


6.83 


3.58 


1.92 


.83 


3.50 


1.67 


2.17 


3.67 


5 


2.75 


5.00 


2.75 


7.92 


16.17 


3.58 


1.92 


.75 


2.67 


1.50 


2.33 


3.67 


6 


2.67 


5.08 


2.50 


8.98 


16.50 


3.17 


1 67 


.75 


2.25 


1.50 


3.00 


3.50 


7 


2.50 


5.00 


2.50 


9.50 


14.58 


3.00 


1.67 


.67 


2.00 


1.42 


3.25 


3.17 


8 


2.50 


5.33 


2.67 


8.83 


12.00 


3.00 


1.58 


.67 


1.75 


1.42 


2. as 


3.00 


9 


2.50 


5.42 


3.08 


8.00 


9.92 


3.00 


1.50 


.58 


1.67 


1.42 


2.75 


3.00 


10 


2.50 


6.42 


6.50 


8.42 


8.25 


2.83 


1.50 


.58 


1.50 


1.33 


2.50 


2.92 


11 


2 25 


7.75 


12.50 


10.00 


7.00 


2.67 


1.50 


.50 


1.50 


1.33 


2.50 


2.83 


12 


2.h 


11.58 


13.83 


9.42 


6.17 


2.58 


1.50 


.50 


1.67 


1.33 


2.42 


2.83 


13 


2.08 


7.50 


14.50 


8.42 


5.50 


2.50 


1.50 


.42 


2.00 


1.25 


2.33 


2.83 


14 


2.08 


6.50 


14.58 


7.75 


5.00 


2.33 


1.50 


.42 


2.00 


1.67 


2.17 


2.50 


15 


2.08 


5.58 


13.00 


7.42 


4.75 


2.08 


1.75 


.42 


1.83 


4.67 


2.08 


2.00 


16 


2.00 


5.25 


12-25 


8.08 


4.58 


2.00 


1.83 


.33 


2.00 


5.33 


2.00 


2.25 


IT 


2.00 


7.75 


10.50 


8.83 


5.92 


1.92 


1.83 


.33 


2.50 


5.25 


1.92 


2 42 


18 


2.00 


6.75 


8.83 


8.92 


8.50 


1.83 


1.67 


.33 


2.67 


4.25 


1.83 


5^75 


19 


2.00 


5.83 


7.33 


7.75 


9.75 


1.75 


1.67 


.33 


4.42 


3.83 


1.75 


8.83 


20 


2.00 


5.33 


6.67 


6.92 


9.00 


1.75 


1.67 


.67 


3.67 


3.42 


1.75 


7.08 


21 


2.00 


4.67 


5.92 


7.00 


7.58 


1.75 


1.67 


.58 


3.25 


3.00 


1.67 


6.00 


o-> 


2.00 


4.25 


5.58 


10.00 


7.00 


1.58 


1.50 


.50 


2.83 


2.50 


158 


5.92 


23 


2.00 


3.50 


5.67 


10.92 


6.25 


1.58 


1.42 


.42 


2.50 


2.50 


1.58 


4.42 


24 


2.00 


3.00 


6.83 


10.50 


5.58 


1.75 


1.33 


.42 


2.33 


2.33 


1.67 


3.92 


25 


2.00 


3.00 


7.25 


8.92 


5.42 


1.75 


1.25 


.a3 


2.33 


2.25 


1.67 


3.83 


26 


2.00 


3.00 


7.75 


7.67 


4.92 


2.00 


1.17 


.42 


2.17 


2.25 


1.58 


3.83 


27 


2.00 


2.92 


9.42 


6.83 


4.50 


2.25 


1.08 


.50 


2.00 


2.25 


1.58 


4.83 


28 


2.00 


2.75 


8.67 


6.17 


4.33 


2.50 


1.08 


.50 


2.00 


2^00 


1.75 


5.92 


29 


2.00 




7.83 


5 67 


4.17 


2.75 


1.83 


1.00 


2.00 


2.00 


2- 83 


5.83 


30 


2.33 




7.83 


5.17 


3.92 


2.50 


.92 


3.00 


2.00 


2.00 


3.67 


5.18 


31 


2.50 




6.50 




3.67 




.92 


3.08 




2.17 




4.67 



Daily Gage Height, in Feet, of Susquehanna River at Harrisburg, 
Pennsylvania, for 1894. 



>> 

Q 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


4.5 


2.41 


3.16 


3.83 


4.58 


9.50 


2.58 


1.08 


0.33 


1.91 


5.08 


2.41 


2 


4.5 


2.33 


3. as 


3.66 


4.50 


9.66 


2.41 


1.08 


.33 


1.83 


5.25 


2.33 


3 


4.0 


2.25 


3.50 


3.50 


4.16 


9.16 


2.33 


1.33 


.33 


1.58 


5.41 


2.50 


4 


3.66 


2.16 


3.75 


3.25 


3.83 


8.58 


2.25 


1.50 


.33 


1.58 


7.50 


2.91 


5 


3.5 


2.08 


4.08 


3.16 


3.50 


S.41 


2.00 


1.66 


.25 


1.41 


7.66 


3.50 


6 


3.33 


2.00 


5.66 


3.00 


3.16 


7.91 


2.00 


1.58 


.25 


1.41 


7.58 


3.58 


7 


3.41 


2.00 


7.66 


2.91 


3.25 


6.75 


1.83 


1.50 


.33 


1.33 


7.16 


3.58 


8 


5.16 


2.00 


11.33 


2.83 


3.33 


6.00 


1.83 


1.50 


.33 


1.33 


7.00 


3.33 


9 


5.25 


2.08 


12.16 


2.75 


3.50 


5.50 


1.75 


1.08 


.41 


1.25 


6.50 


3.00 


10 


4.58 


3.50 


10.83 


2.75 


3.50 


5.00 


1.66 


1.08 


1.00 


1.33 


6.00 


3.00 


11 


3.75 


5.00 


, 8.50 


2.83 


3.50 


4.66 


1.58 


1.08 


1.91 


2.08 


5.50 


3.33 


12 


3.33 


6.00 


9.83 


3.00 


3.08 


4.00 


1.50 


1.00 


1.50 


4.91 


5. as 


4.00 


13 


2.50 


5.66 


7.16 


3.25 


2.91 


3.75 


1.41 


1.00 


1.33 


5.58 


4.66 


4.33 


14 


3.16 


4.58 


7.00 


3.66 


2.75 


3.66 


1.41 


1.00 


1.25 


5.08 


4.50 


5.75 


15 


3.16 


4.33 


| 6.41 


6.33 


2.50 


3.66 


1.33 


1.00 


1.25 


4.66 


4.00 


6.16 


16 


2.83 


3.66 


j 5.83 


7.5S 


2.50 


3.58 


1.33 


1.00 


1.16 


4.16 


3.91 


6.33 


17 


2.66 


3.33 


5.50 


9.08 


2.33 


3.41 


1.25 


1.00 


1.08 


3.83 


3.66 


5.75 


18 


2.83 


3.&3 


5.08 


9.08 


2.33 


3.16 


1.16 


1.00 


1.08 


3.66 


3.50 


5.16 


19 


2.83 


3.33 


4.83 


8.50 


2.33 


3.00 


1.08 


.91 


2.16 


3.41 


3.25 


4.66 


20 


3.00 


4.16 


4.58 


7.511 


5.33 


3.50 


1.0S 


.91 


4.08 


3.00 


3.16 


4.33 


21 


2. as 


5.66 


4.50 


6.75 


16.33 


3.41 


1.08 


.83 


5.00 


2.75 


3.08 


4.08 


22 


2. as 


5.33 


4.33 


8.50 


25.58 


3.08 


1.08 


.83 


5.50 


2.50 


3.25 


3.83 


23 


2.58 


5.16 


4.50 


9.41 


21.41 


2.83 


1.00 


.75 


5.66 


2.33 


3.16 


3.58 


24 


2.41 


4.33 


4.66 


9.58 


15.25 


2.50 


1.08 


.75 


4.83 


2.16 


3.00 


3.50 


25 


2.41 


3.33 


5.50 


9.91 


11. S3 


2.50 


1.25 


.75 


4.00 


2.33 


3.00 


3.33 


26 


2.41 


2.91 


7.00 


9.00 


11.33 


2.66 


1.41 


.75 


3.41 


3.58 


2.83 


3.08 


27 


2.41 


2.33 


ti.:i:i 


7.25 


11.66 


8.58 


1.50 


.till 


3.00 


4.75 


2.66 


3 00 


28 


2.50 


2.50 


5.50 


6.00 


9.5(1 


2. tit; 


1.50 


.66 


2.5S 


4. S3 


2.58 


3.00 


29 


2.58 




4.91 


5.41 


7.91 


2.41 


1.41 


.58 


2.25 


4.33 


2.58 


4.00 


30 


2.58 




4.33 


5.00 


7.00 


2.75 


1.16 


.50 


2. OS 


4.00 


2.50 


3.66 


31 


2.50 




4.00 




7.50 




1.08 


.41 




3.75 




3.66 



278 



THE HYDROGRAPHY OF CECIL COUNTY 



Daily Gage Height, in Feet, of Susquehanna River at Hakrisburg, 
Pennsylvania, for 1895. 



eS 
Q 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


3.92 


2.92 


6.00 


5.75 


3.42 


2.67 


2.83 


0.58 


0.75 


0.42 


0.21 


3.08 


?, 


4.00 


2. S3 


8.58 


5.67 


3.33 


2.58 


2.67 


.67 


.75 


.42 


.21 


3.08 


3 


4.25 


3.00 


s.os 


6.17 


3.25 


2.50 


2.'. 12 


.67 


.67 


.33 


.25 


2.75 


4 


4.33 


3.00 


10.50 


6. S3 


3.00 


2.25 


2.50 


.67 


.67 


.33 


.25 


2.50 


5 


4.33 


7.00 


7.83 


6.67 


2.75 


2.08 


2.25 


.58 


.58 


.33 


.33 


2.25 


li 


4.33 


5.67 


7.67 


6.17 


2.67 


1.92 


2.00 


.50 


.58 


.33 


.38 


2.00 


7 


4.33 


5.75 


6.67 


6.00 


2.50 


1.83 


1.92 


.50 


.75 


.33 


.38 


1.92 


8 


4.50 
4.75 


5.67 


6.25 


5.75 


2.42 


1.75 


1.75 


.83 


.75 


.25 


.42 


1.92 


q 


5.50 


5.83 


8.08 


2-25 


1.75 


1.58 


.75 


.67 


.25 


.42 


1 92 


in 


6.17 


5.50 


6.17 


12.00 


2.75 


1.58 


1.50 


1.00 


.50 


.21 


.42 


1.83 


n 


7.42 


5.58 


6.17 


13.67 


3.00 


1.33 


1.50 


1.08 


1.00 


.21 


.42 


.50 


v 


7.K3 


5.92 


6.33 


12.50 


3.33 


1.42 


1.42 


1.08 


1.50 


.21 


.46 


1.50 


13 


8.50 


5.83 


6.17 


10.92 


3.67 


1.33 


1.33 


1.08 


1.58 


.33 


.50 


.96 


14 


7.83 


5.83 


6.00 


it. 50 


4.33 


1.25 


1.33 


.92 


1.42 


.29 


.58 


.75 


15 


6.75 


5.67 


6.50 


10.00 


4.33 


1.25 


1.25 


1.33 


1.00 


.29 


.58 


1.00 


16 


6.25 


5.58 


6.75 


9.75 


4.17 


1.25 


1.25 


1.33 


.83 


.25 


.58 


1.00 


17 


5.75 


5.50 


6.67 


8.75 


4. OS 


1.25 


1.08 


1.08 


.67 


.25 


.67 


1.33 


18 


5.42 


5.50 


6.33 


7.58 


3.67 


1.25 


1.00 


1.00 


.58 


.42 


.83 


1.33 


19 


5.00 


5.33 


5.67 


6.67 


3.50 


1.25 


.92 


1.00 


.67 


.58 


1.00 


1.33 


20 


4.50 


5.25 


5.50 


6.00 


3.33 


1.25 


.92 


.92 


.67 


.50 


1.00 


1.33 


n 


4.42 


5.17 


5.33 


5.50 


3.17 


1.17 


.83 


.83 


.67 


.42 


.92 


1.50 


?■?, 


4.33 


5.08 


5.17 


5.00 


3.08 


1.00 


.83 


.58 


.58 


.42 


.79 


1.S3 


23 


4.00 


5.00 


5.00 


4.58 


2.92 


.75 


.83 


.50 


.58 


.33 


.67 


2.00 


"4 


4.00 


4.92 


5.00 


4.33 


2.75 


.75 


.83 


.50 


.58 


.25 


.75 


2.67 


25 


3.33 


4.75 


5.00 


4.00 


2.58 


75 


.S3 


.42 


.58 


.25 


.15 


2.75 


?6 


3.25 


4.58 


5. S3 


3.75 


2.50 


1.50 


.83 


.33 


.50 


.21 


.75 


2. S3 


?,7 


3.08 


4.50 


8.00 


3.58 


2.50 


1.50 


.83 


.33 


.50 


.13 


.75 


3.33 


"8 


3. (IS 


4.75 


9.00 


3.75 


2.42 


1.50 


.83 


.33 


.42 


.08 


2.67 


3.50 


29 


3.08 




8.00 


3.75 


2.42 


2.00 


.75 


.33 


.42 


.08 


2. S3 


5.08 


30 


3.25 




7.17 


3.50 


3.08 


3.50 


.58 


.33 


.42 


.04 


2.83 


5.67 


31 


3.00 




6.33 




3.00 




.42 


.50 


.... 


.04 




5.67 



Daily Gage Height, in Feet, of Susquehanna River at Harrisburg, 
Pennsylvania, for 1896. 





Jau. 


Feb. 


March 


April 


May 


Juue 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


9.92 


4.50 


7.17 


14.58 


3.00 


1.50 


2.67 


4.67 


0.33 


5.42 


2.08 


3.92 


2 


9.17 


3.75 


9.17 


14.5S 


3.00 


1.50 


2.42 


4.33 


.33 


4.25 


1.92 


3.92 


3 


8.42 


3.58 


9.75 


13.75 


2. S3 


1.75 


2.08 


3.83 


.33 


4.00 


1.83 


3.83 


4 


6 50 


3.58 


8.42 


12. 33 


2.83 


1.83 


1.83 


3.75 


.33 


3.17 


1.83 


3. S3 


5 


5.08 


3.50 


7.17 


10.50 


2.67 


1.67 


1.75 


3.117 


.25 


2.67 


1.83 


3.00 


fi 


I.IKI 


4.00 


5.50 


S.S3 


2.50 


1.67 


1.67 


3.58 


.25 


2.08 


7.25 


2.75 


7 


3. S3 


11.50 


5.00 


7.25 


2.42 


1.67 


2.17 


2.50 


.25 


1.83 


10.08 


2.67 


8 


3.00 


12.5(1 


4.75 


6.50 


2.17 


1.5S 


2.00 


2.33 


.25 


1.67 


7.75 


2.50 


9 


4.67 


10.33 


4.50 


6.17 


2.08 


1.42 


1.92 


2.33 


.25 


1.50 


6.50 


2.5(1 


10 


4.33 


8.50 


4.83 


5. S3 


2.00 


1.75 


2.33 


2.25 


.25 


1.50 


5.67 


2.67 


11 


4.08 


6. S3 


5.08 


5.50 


2.00 


2.50 


2.75 


2.25 


.25 


1.50 


4.75 


3.42 


1? 


4.00 


5.33 


4.67 


5.50 


1.92 


2.5S 


2.75 


2.00 


.25 


1.50 


4.42 


3.75 


13 


3.92 


4.92 


4.00 


6.00 


1.75 


3.42 


2.50 


1.S3 


.25 


1.92 


4.17 


4.00 


14 


4.00 


4.25 


3.50 


6.42 


1.67 


3.25 


2.17 


1.67 


.33 


7.88 


4.00 


4.25 


15 


3.83 


:;.',:, 


2.67 


S.00 


1.67 


2.92 


2. (HI 


1.67 


.33 


7.00 


3.83 


3.83 


16 


3.83 


3.75 


2.67 


8.42 


1.75 


2.58 


1.83 


1.58 


.33 


9.50 


3.67 


3.67 


17 


3.75 


3.83 


2.33 


8.17 


1.58 


2.5S 


1.67 


L.68 


.50 


7.117 


3.50 


3.42 


18 


3.5S 


3.5S 


2.50 


7.33 


1.50 


2. S3 


1.58 


1.58 


.60 


5.5S 


3.33 


3.08 


19 


3.67 


2.92 


3.17 


6.83 


1.50 


2.67 


1.67 


1.33 


.58 


4.83 


3.17 


2 . 92 


•Ml 


4.00 


3.00 


4.00 


6.33 


1 50 


3.00 


1.67 


1.25 


.58 


4.08 


3.00 


2.5S 


-1 


3.67 


2.33 


6.00 


5.75 


1.50 


8.11 


1.92 


I.IKI 


.67 


3.5S 


2. S3 


2.33 


•>•> 


3.50 


3.67 


5.75 


5.25 


1.42 


3.00 


1.67 


.83 


.83 


3.42 


2.67 


2.IMI 


"3 


8.50 


5.42 


5.75 


1.83 


1 . 12 


2. 12 


1.58 


.S3 


1.17 


3.25 


2.58 


2.00 


24 


3.60 


6.42 


6.26 


1.58 


1.42 


2.88 


1.67 


.S3 


1.17 


3.00 


2.50 


1.50 


?Jn 


4.00 


8.42 


;,.:,* 


4.33 


L.33 


2.25 


L.61 


.83 


.92 


3. (HI 


2.50 


1.50 


•'6 


7.25 


3.60 


5.00 


4. OS 


1.25 


2.67 


1.75 


.75 


.75 


3.00 


2.33 


1.50 


fn 


7.33 


3.67 


5.25 


I.IKI 


1.17 


t.75 


1.92 


.75 


.58 


2.75 


2.33 


1.50 


-s 


6.17 


3.17 


6.08 


3.58 


1.25 


I.IKI 


2.50 


.67 


.50 


2.67 


2.42 


1.50 


.»(, 


6.00 


3.17 


6.50 


:;. I'.' 


1.50 


3.60 


2.50 


.58 


.42 


2.50 


2.61 


1.33 


:;n 


5 . ', 5 




9.25 


3.25 


1.50 


3.08 


3.75 


.50 


.83 


2.42 


3.50 


1.58 


31 


5.42 




12.50 




1.50 


| .... 


I 4.33 


.33 




2.25 




1 . 75 



MARYLAND GEOLOGICAL SURVEY 



279 



Daily Gage Height, in Feet, of Susquehanna River at Hakrisburg, 
Pennsylvania, for 1897. 



ft 


Jan. 


Feb. 


March 


April 
5.00 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


1.83 


3.33 


4.25 


3.08 


2.92 


1.42 


4.00 


1.25 


1.75 


0.67 


5.00 


2 


2.00 


3.17 


3.67 


4.67 


3.08 


2. 83 


1.33 


4.33 


1.08 


1.50 


1.17 


4.50 


3 


2.00 


3.17 


3.25 


4.33 


5.50 


2.67 


1.25 


3.83 


1.00 


1.33 


3.08 


4.00 


4 


2.08 


3.17 


3.83 


4.17 


6.50 


2.58 


1.25 


3.25 


1.00 


1.17 


4.08 


3.75 


5 


2.50 


3.08 


4.92 


4.00 


7.50 


2.67 


1.25 


2.83 


1.00 


1.08 


3.50 


3.33 


6 


3.00 


3.00 


5.92 


3.83 


7.08 


3.00 


1.25 


2.67 


.92 


1.00 


3. OS 


4.75 


7 


3.67 


4.25 


7.67 


3.75 


7.00 


2.67 


1.42 


2.42 


.83 


1.00 


3.00 


5.17 


8 


3.67 


7.50 


8.58 


3.75 


6.33 


2.50 


1.42 


2.67 


.83 


.92 


2.75 


5.08 


9 


3.67 


6.58 


8.00 


3.75 


5.50 


2.67 


1.25 


2.50 


.83 


.83 


2.50 


5.42 


10 


3.33 


5.42 


6.92 


5.92 


4.83 


2.67 


1.25 


2.08 


.83 


.67 


2.50 


4.92 


11 


3.08 


4.83 


6.50 


9.00 


4.50 


2.67 


1.17 


2.08 


.75 


67 


2.67 


4.33 


12 


2.83 


4.50 


7.25 


9.50 


4.00 


2.67 


1.08 


2.00 


.67 


.58 


2.67 


4.17 


13 


2.42 


3.92 


8.67 


8.00 


4.00 


3.00 


1.00 


1.83 


.67 


.75 


2.50 


4.17 


14 


2.00 


3.83 


8.42 


6.83 


6.00 


3.50 


1.08 


1.75 


.67 


.75 


2.50 


4.33 


15 


2.00 


3.83 


7.75 


6.00 


7.75 


3.25 


1.00 


1.58 


.50 


.75 


2.50 


4.58 


16 


2.00 


3.50 


7.00 


6.00 


7.92 


2.92 


1.00 


1.58 


.58 


.75 


2.50 


6.58 


17 


2.00 


3.50 


6.92 


6.58 


7.33 


2.67 


1.17 


1.50 


.67 


.67 


2.50 


7.67 


18 


2.17 


3.33 


5.50 


7.00 


6.50 


2.50 


1.17 


1.50 


.75 


.67 


2.67 


8.17 


19 


2.33 


3.58 


5.00 


6.58 


5.75 


2.25 


1.08 


1.42 


.75 


.58 


2.92 


7.33 


20 


2.00 


4.08 


5.33 


6.00 


5.00 


2.17 


1.08 


1.42 


.67 


.58 


3.42 


6.33 


21 


1.83 


4.00 


7.42 


5.50 


4.25 


2.17 


1.50 


1.33 


.58 


.58 


3.25 


5.58 


22 


1.83 


4.25 


8.25 


4.92 


4.00 


2.17 


1.50 


1.17 


.58 


.58 


3.17 


5.00 


23 


1.92 


5.92 


9.75 


4.50 


3.58 


2.00 


1.33 


1.17 


.58 


.75 


2.83 


4.08 


24 


1.67 


7.92 


9.50 


4.17 


3.50 


1.83 


1.33 


1.25 


1.00 


.75 


2.50 


3.83 


25 


1.67 


7.50 


10.17 


3.83 


3.75 


1.75 


1.58 


1.67 


1.50 


1.00 


2.50 


3.42 


2ii 


.50 


6.50 


11.511 


3.67 


3.75 


1.75 


1.75 


2.67 


1.50 


1.00 


2.50 


2.83 


27 


3.313 


5.50 


10.67 


3.58 


3.50 


1.67 


1.75 


2.08 


1.83 


1.00 


2.33 


2.75 


28 


3.33 


4.50 


8.00 


3.50 


3.58 


1.58 


2.17 


1.75 


1.92 


.92 


2.50 


2.67 


29 


3.00 




7.42 


3.33 


3.92 


1.58 


3.83 


1.58 


2.25 


.83 


3.50 


2.67 


30 


3.25 




6.33 


3.17 


3.50 


1.50 


4.50 


1.50 


2.00 


.75 


4.92 


2.58 


31 


3.33 




5.58 




3.25 




4.08 


1.33 




.75 




2.50 



Daily Gage Height, in Feet, of Susquehanna River at Harrisburg, 
Pennsylvania for 1898. 



>> 
Q 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


2.66 


3.91 


4.66 


8.66 


6.00 


4.33 


2.00 


1.41 


2.66 


0.75 


4.66 


3.08 


2 


2.33 


3.41 


4.33 


7.41 


5.41 


4.16 


2.16 


1.50 


2.33 


.75 


4.00 


3.16 


3 


2.16 


3.00 


4.16 


6.41 


4.83 


3.91 


2.00 


1.41 


3.00 


.66 


3.66 


3.08 


4 


2.66 


2.66 


3.91 


5.75 


4.66 


3.58 


1.75 


2.33 


2.50 


.66 


3.50 


3.00 


5 


1.91 


2.66 


3.66 


5.41 


4.41 


3.33 


1.66 


4.58 


2.08 


.66 


3.16 


3.66 


6 


1.91 


2.66 


3.58 


4.91 


4.43 


3.00 


1.58 


5.33 


1.91 


.06 


3.00 


5.00 


7 


2.25 


2.66 


3.50 


4.50 


4.66 


2.83 


1.50 


4.00 


1.66 


.66 


2.91 


4.50 


8 


2! 50 


3.08 


3.50 


4.41 


5.50 


2.66 


1.41 


3.50 


1.66 


1.00 


2.50 


4.08 


9 


2.66 


3.41 


3.33 


4.16 


6.25 


2.50 


1.33 


3.08 


1.66 


1.33 


2.50 


3.83 


10 


2.75 


3.50 


3.33 


3.83 


5.58 


2.50 


1.25 


3.66 


2.00 


1.41 


2.50 


3.58 


11 


3.00 


3.41 


3.83 


3.66 


5.16 


2.33 


1.16 


4.25 


2.83 


2.25 


2.58 


3.08 


12 


3.00 


3.75 


4.91 


3.50 


4.75 


2.33 


1.08 


3.75 


2.75 


2.40 


4.00 


2.50 


13 


3.33 


4.41 


6.50 


3.&3 


4.50 


2.25 


1.00 


3.33 


2.58 


2.33 


8.75 


2.25 


14 


4.00 


7.66 


8.66 


3.25 


4.00 


2.25 


.91 


2.66 


2.08 


2.00 


8.00 


2.25 


15 


6.95 


8.16 


9.83 


3.16 


4.00 


2.41 


.83 


2.50 


1.91 


2.00 


6.58 


2.08 


16 


8.08 


7.50 


9.33 


3.66 


4.25 


2.75 


.83 


2.25 


1.75 


2.08 


5.50 


2.00 


17 


7.83 


6.50 


8.08 


4.08 


5.16 


3.25 


.75 


2.00 


1.41 


2.16 


4.83 


2.00 


18 


7.58 


5.83 


7.16 


3.91 


6.08 


3.00 


.66 


1.91 


1.33 


3.25 


4.33 


1.91 


19 


6.58 


5.00 


6.33 


3.66 


5.33 


2.66 


.66 


2.33 


1.16 


3.75 


4.16 


2.00 


20 


5.83 


4.33 


5.83 


3.50 


5.50 


2.41 


.75 


3.00 


1.00 


4.00 


4.16 


2.50 


21 


5.75 


4.66 


7.33 


3.41 


6.66 


2.. 33 


.91 


4.41 


.91 


4.33 


4.25 


2.91 


22 


6.16 


6.83 


9.25 


3.33 


6.66 


2.33 


.75 


4.33 


.91 


4.25 


4.58 


3.08 


23 


7.41 


b.91 


10.91 


3.16 


6.50 


2.08 


.91 


3.75 


.91 


7.33 


4.83 


3.50 


24 


9.25 


7.75 


15.63 


3.00 


6.00 


2.00 


.83 


3.41 


.83 


8.33 


4.66 


5.41 


25 


10.50 


6.66 


15.25 


3.50 


7.00 


2.16 


.813 


3.00 


.83 


7.41 


4.33 


7.83 


26 


9.50 


6.25 


11.66 


6.66 


6.50 


2.08 


.83 


2.66 


.75 


6.16 


4.00 


7.66 


27 


8.00 


5.66 


9.25 


10.33 


6.50 


2.00 


1.33 


2.50 


.91 


5.66 


3.91 


6.33 


28 


7.00 


5.00 


7.75 


9.50 


6.16 


1.91 


1.16 


2 41 


.91 


5.58 


3.66 


5.33 


29 


6.08 | 




6.66 


8.16 


5.75 


1.83 


1.83 


4.16 


.75 


5.66 


3.50 


4.83 


30 


5.50 




7.00 


6.66 


5.33 


1.66 


1.58 


3.83 


.75 


6.08 


3.33 


4.33 


31 


4.83 




9.00 




4.91 




1.33 


3.00 


.... 


5.33 




3.83 



280 



THE HYDROGRAPHY OF CECIL COUNTY 



Daily Gage Height, in Feet, of Susquehanna Rivek at Harrisburg, 
Pennsylvania, for 1899. 



>> 

o 


Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


1 


3.25 


2.50 


8.41 


7.25 


3.41 


2.50 


1.75 


0.75 


1.83 


1.08 


0.50 


1.75 


2 


3.16 


2.00 


8.16 


6.41 


3.08 


2.58 


1.66 


.75 


1.50 


.83 


1.66 


1.58 


3 


2.75 


1.91 


7.83 


5.83 


3.08 


2.50 


1.66 


.75 


1.25 


.83 


2.50 


1.50 


4 


3.25 


2.25 


7.41 


5.33 


3.41 


2.50 


1.50 


.75 


1.08 


.75 


3.25 


1.50 


5 


3.50 


2. 58 


8.00 


4.91 


3.16 


2.50 


1.33 


.75 


1.08 


.11(1 


4.50 


1.50 


6 


5.00 


2.66 


13.50 


4.41 


3.16 


2.33 


1.25 


.91 


1.00 


.66 


3.91 


1.50 


7 


8.00 


2.83 


13.00 


4.25 


3.00 


2.08 


1.25 


.75 


.91 


.58 


3.75 


1.50 


8 


6.83 


2.41 


11.41 


4.75 


2.75 


1.91 


1.16 


.75 


.91 


.58 


3.16 


1.50 


9 


6.08 


2.50 


9.25 


6.83 


2.83 


1.91 


1.16 


.83 


.83 


.58 


2.83 


1.50 


10 


5.41 


2.41 


7.66 


8.75 


2.66 


1.91 


1.16 


.75 


1.00 


.66 


2.50 


1.50 


11 


4.58 


2.41 


6.50 


8.41 


2.75 


1.75 


1.41 


.66 


1.00 


.58 


2 . 25 


1.50 


12 


4.00 


4.41 


5.75 


7.75 


2.75 


1.66 


1.25 


.66 


.75 


.58 


2A6 


1.50 


13 


3.33 


4.41 


5.75 


6.75 


2.91 


1.66 


1.16 


1.08 


.83 


.50 


2.08 


3.75 


14 


3.16 


4.58 


7.50 


6.75 


2.83 


1.58 


1.16 


1.08 


1.41 


.50 


2.00 


5.50 


15 


3.33 


4.58 


8.41 


8.00 


2.58 


1.50 


1.16 


1.25 


1.25 


.51 


2.35 


6.33 


16 


3.66 


4.66 


8.00 


S.00 


2.50 


1.50 


1.08 


.91 


.83 


.41 


2.41 


6.00 


17 


4.83 


4.83 


7.41 


7.83 


2.50 


1.41 


1.00 


.66 


.75 


.41 


2.41 


5.33 


18 


7.00 


4.83 


6.41 


7.33 


2.58 


1.25 


1.25 


.66 


.75 


.41 


2.41 


4.58 


19 


6.33 


4.91 


4.33 


6.83 


3.75 


1.25 


1.25 


.50 


.58 


.41 


2.83 


4.08 


30 


5.66 


4.75 


7.16 


6.00 


4.75 


1.25 


1.25 


.50 


.66 


.33 


3.00 


3.75 


21 


4.91 


4.91 


8.50 


5.41 


5.16 


1.25 


1.25 


.50 


.75 


.33 


2.91 


3.75 


23 


4.33 


5.33 


8.16 


5.08 


4.25 


1.16 


1.33 


.50 


.66 


.33 


2.58 


3.83 


23 


4.25 


7.50 


7.50 


4.91 


3.91 


1.08 


1.33 


.50 


.66 


.33 


2.50 


4.50 


24 


4. US 


7.50 


7.16 


4.50 


3.58 


1.00 


1.33 


.50 


.66 


.16 


2.25 


4.25 


25 


4.16 


7.16 


7.41 


4.41 


3.16 


1.41 


1.16 


.50 


.66 


.16 


2.35 


5.83 


26 


5.25 


6.813 


7.41 


4.00 


3.00 


2.00 


1.00 


.41 


.66 


.25 


2.25 


6.75 


27 


4.50 


7.33 


6.83 


3.91 


2.91 


1.66 


1.00 


.66 


1.00 


.33 


2.16 


5.25 


28 


3.83 


9.00 


6.33 


3.75 


2-66 


1.50 


1.00 


4.00 


1.33 


.33 


2.00 


4.58 


29 


3.25 




6.83 


3.66 


2.50 


1.50 


.91 


2.66 


1.16 


.41 


2.00 


3.83 


30 


3.IKI 




7.83 


3.50 


2.50 


1.75 


.83 


2.50 


1.08 


.33 


1.83 


3.00 


31 


3.00 




8.08 




2.50 


.... 


.75 


2.16 




.33 




2.25 



Daily Gage Height, in Feet, of Susquehanna River at Harrisburg, 
Pennsylvania, for 1900. 





Jan. 


Feb. 


March 


April 


May 


June 


July 


Aug. 


Sept. 
1.00 


Oct. 


Nov. 


Dec. 


1 


1.83 


2.91 


4.00 


4.16 


4.00 


2.58 


1.17 


1.35 


0.04 


0.83 


7.00 


2 


Mill 


1.83 


13.13 


4.00 


3.75 


2.50 


1.08 


1.00 


1.00 


.04 


.83 


5.83 


3 


4.50 


3.91 


12.33 


4.16 


3.50 


2.33 


1.00 


1.00 


.83 


.04 


.75 


5.35 


-t 


4.91 


4.00 


9.50 


4.41 


3.33 


2.17 


1.08 


.92 


1.17 


.0(1 


.75 


4.50 


5 


1.83 


4.66 


7.91 


5.33 


3.08 


3.50 


1.33 


.75 


.92 


.04 


.75 


5. (HI 


6 


5.35 


4.33 


(1.91 


6.00 


2.83 


3. (17 


1.17 


.67 


.83 


.04 


.66 


7.35 


1 


5.50 


5.50 


6.00 


5.41 


2.83 


2.50 


1.33 


.(17 


.58 


.04 


.in; 


7.41 


8 


5.33 


5.00 


(1.1(1 


5.08 


3.75 


2.17 


1.17 


.58 


.58 


.08 


.66 


7. os 


9 


4.91 


4.00 


6.50 


6.16 


3.50 


2.17 


1.42 


.50 


.58 


.04 


.75 


6.00 


10 


4.58 


4.83 


5.83 


6.75 


2.50 


2.08 


1.42 


.58 


.50 


.01 


.58 


5 . 25 


11 


4.50 


5 . 75 


5.(1(1 


6.50 


2.42 


2.00 


1.33 


..-,o 


.43 


.04 


.(id 


4.75 


13 


5.511 


.-,..-,0 


(1.25 


5.58 


2.33 


2.00 


1.17 


.33 


.33 


.04 


.50 


4. OS 


13 


4.91 


5.66 


5.75 


5.00 


3.43 


1.93 


1.08 


.3:; 


.17 


.35 


.58 


3.83 


14 


.-,.:.'.-, 


7.iHi 


4.66 


4.50 


2.42 


1.9:.' 


1.08 


.35 


.35 


.83 


• 75 


3.60 


15 


:,.:::, 


8.00 


t..-,ii 


4.33 


2.50 


3. (Ml 


1.00 


.17 


.35 


.S3 


.(Hi 


3.91 


16 


:,.3.-, 


8.26 


1.00 


4.50 


2.40 


3.17 


1.00 


.17 


.35 


.75 


.66 


3. 85 


17 


1.66 


7.41 


3.6(1 


4.41 


2.33 


3.17 


1.00 


.35 


.35 


.58 


.83 


2.25 


18 


5. (HI 


6.00 


3.16 


4.:ci 


2.33 


2.00 


1.08 


.17 


.17 


.mi 


.!U 


2.08 


l!i 


1.83 


4.-,:, 


3.00 


5. OS 


3.35 


L.83 


.92 


.17 


• OS 


.(id 


.75 


3. os 


20 


(.110 


3.91 


:i.(Ki 


7.08 


2.50 


1.83 


.92 


.17 


.13 


.58 


.91 


3. OS 


21 


!.:.•:, 


3.1U 


3.91 


7.33 


2.93 


l.s:.' 


.83 


.33 


.08 


.50 


.91 


3. (HI 


22 


10.66 


3.58 


(1.87 


6.83 


2.Ti 


1.-,:, 


.75 


.43 


.07 


.50 


.91 


2.16 


23 


13. (Kl 


9.50 


6.83 


6.08 


3.83 


1.75 


.75 


.83 


.0(1 


.50 


.83 


3.41 


24 


9.16 


11. HI 


ti.oo 


5. S3 


3.5S 


1.58 


.75 


.50 


.01 


.50 


1.00 


3.1(1 


35 


: . -.'.-, 


9.75 


5.75 


6.00 


2. 1'.' 


1 . 13 


.-.:, 


1.35 


.04 


1.00 


l.os 


2.33 


26 


11.08 


(1.83 


5.83 


(1.35 


2 "5 


L.33 


.83 


1.00 


.02 


l.os 


l.iiii 


3.41 


37 


:,.oo 


5.50 


5.50 


5.75 


3M7 


1.33 


1.50 


1.17 


.(HI 


1.00 


5.91 


3. (HI 


38 


4.50 


1.50 


5.35 


5.08 


3. (HI 


1.33 


1.25 


1.50 


-0.04 


1.25 


13.04 


3.(1(1 


39 


I.IIS 




4.S1S 


4.58 


3.00 


1.33 


1.25 


i.:;:; 


-0.04 


1.16 


12.33 


2.91 


30 


:;.:;:; 




4.50 


4.17 


2.00 


1.17 


1.42 


1.00 


HI. 04 


1.00 


8.91 


2.58 


ill 


'.•.:,ii 


.... 


l.ll 


1 


1.93 


.... 


1.35 


l.os 


.... 


.91 




2.50 



MARYLAND GEOLOGICAL SURVEY 281 

Rating Table for Susquehanna River at Harrisburg, Pennsylvania, 1899. 



*5 




to 


c 


(D 


60 


3 


cS 




.3 






tS 


Q 


Ft. 


Second-Ft. 


.0 


3,000 


.1 




•_> 


3,650 


.% 




A 


4,350 


.5 




.6 


5,050 






.8 


5,900 


.4 




l.i 


7,000 


.1 




,9 


8,200 


.:- 




A 


9,450 


.5 




.6 


10,750 


"j 




.8 


12,300 


.41 





Second-Ft 

13,900 

1 ... 

2 15,500 

3 ... 

4 17,300 

51 ... 

6 19,300 

7 ... 

8 21,300 



23,400 
25,625 
27,925 
30,300 
32,800 



Ft. Second-Ft. 

4.0 35,400 

.1 
4.2 

.3 
4.4 

.5 

t.e 



38,100 
41,100 
44,590 
48,170 
51,750 
55,330 
58,910 
62,490 
5.8 66,676 



Second-Ft. 



7.5 



O 



Ft. iSecond-Ft. 



Ft. 



Second-Ft. 



69,650 8.0 105,450 10.0, 141,250 



73,230 
76,810 
8b',390 
83,970 
87,550 



96,500 



.1 



.9 

9.0 

.1 

■> 

i 



114,400 



.1 



10.5 150,200 



123,&50 



9.5! 132,300 

•6 

.7 

.8 



•9, 
11.0 159,150 

•1 
.2 
.3 

■M 
11.5 



168,100 



Ft. Second-Ft, 



12.0 
.1 
.2 
.3 
.4 

L2.5 
.6 
.7 



13.0 
.1 
.2 
.3 
.4 

13.5 
.6 
.7 



Ft. 

177,050 14.0 
.1 
.2 
.3 

.4 
14.5 



Second-Ft. 
212,850 



186,000 



194,95(1 



203,900 



221,800 



230,750 



15.0 

.1 

.2 

.3 

.4 I 

15.5 239,700 

16.00 24K,t>50 

16.50 257,600 

17.00 266.551 1 



Rating Table for Susquehanna River at Harrisburg, Pennsylvania, for 1897. 



Gage 
height. 


Discharge. 


Gage 
height. 


Discharge. 


Gage 
height. 


Discharge. 


Gage 
height. 


Discharge. 


Feet. 


Second-feet. 


Feet. 


Second-feet. 


Feet. 


Second-feet. 


Feet. 


Second-feet. 


0.0 


2,000 


2.6 


19,300 


5.5 


61,090 


12.0 


177,040 


2 


2,800 


2.8 


21,300 


6.0 


69,990 


12.5 


185,990 


0.4 


3,600 


3.0 


23,400 


6.5 


78,890 


13.0 


194,940 


0.6 


4,500 


3.2 


25,550 


7.0 


87,790 


13.5 


203,890 


0.8 


5,700 


3.4 


27,800 


7.5 


96,690 


14.0 


212,840 


1.0 


6,900 


3.6 


30,400 


8.0 


105,590 


14.5 


221,790 


1.2 


8,150 


3.8 


32,800 


8.5 


114,490 


15.0 


230,740 


1.4 


9,450 


4.0 


35,400 


9.0 


123,390 


15.5 


239,690 


1.6 


10,750 


4.2 


38,150 


9.5 


132,290 


16.0 


248,640 


1.8 


12,300 


4.4 


41,150 


10.0 


141,240 


16.5 


257,590 


2.0 


13,900 


4.6 


44,350 


10.5 


150,190 






2.2 


15,400 


4.8 


47,700 


11.0 


159,140 






2.4 


17,450 


5.0 


51,400 


11.5 


168,000 







282 



THE HYDROGRAPHY OF CECIL COUNTY 



Estimated Monthly Discharge of Susquehanna River at Harrisburg, 

Pennsylvania. 
(Drainage area, 24,030 square miles.) 





DISCHARGE IN SECOND-FEET. 


TOTAL IN 
ACRE FEET. 


RUN- 


•OFF. 


MONTH. 


Maximum. 


Minimum. 


Mean. 


Depth in 
inches. 


Second-feet 

per square 

mile. 


1891 

January 

February 

April 


138,555, 

302,300 

159,140 

123,390 

30,400 

72,675 

40,400 

80,680 

45,150 

45,150 

77,150 

132,290 


21,800 
62,880 
45,150 
33,450 
13,900 
13,100 
12,700 
13,900 
11,900 
10,750 
13,900 
29,100 


73,052 
140,790 
99,105 
81,044 
19,384 
25,630 
21,752 
30,900 
23,649 
18,810 
34,024 
63,289 


4,491,792 
7,819,080 

6,093,728 
4,822,453 

1,191,875 
1,525,091 
1,337,479 
1,899,967 
1,407,214 
1,156,582 
2,024,568 
3,S91,489 
37,661,318 


3 . 5 1 
6.10 
4.76 
3.76 
0.93 
1.19 
1.05 
1.49 
1.09 
0.90 
1.58 
3.03 


3.04 
5.86 
4.12 
3.37 


Mav 


0.81 


June 


1.07 


July 


0.91 


October 


1 . 29 
0.98 
0.78 
1.42 
2.63 


The year. . 


302,300 


10,750 


52,619 


29.39 


2 . 1 9 


1892 
April 


197,625 

48,600 

194,940 

224,475 

120,755 

185,990 

45,150 

37,450 

22,300 

9,450 

30,400 

38,900 


14,600 

7,500 

18,300 

25,025 

21,800 

26,100 

9,4 50 

12,700 

7,510 

4,000 

4,000 

6,300 


80,041 
22,244 
51,578 
80,250 
67,999 
65,704 
1'. 1,469 
18,886 
11,713 
6,255 
11,123 
16,436 


4,921,529 
1,279,489 

3,171,408 

4,775,206 

4,181,095 

3,909,659 

1,197,101 

1,161,255 

696,972 

384,604 

661,865 

1,010,611 

27,350,794 


3.84 
1.00 
2.48 
3.73 
3.26 
3.04 
0.93 
0.91 
0.54 
0.30 
0.52 
0.78 


3.33 
0.93 
2.15 
3.34 


May 


2.83 


June 


2 . 73 


July 


0.81 


September 


0.79 
0.49 
0.26 
0.46 
0.68 


The year. . 


224,475 


4,000 


37,641 


21.33 


1.57 



1893 

January 

February. . . . 

March 

April 

May 

June 

July 

August 

September. . . 

October 

November.. . 

December . . . 

The j ear 



21,800 

169,880 
223,580 
157,350 

257,590 
31,000 
10,775 
24,500 
llJ.Mi 
58,318 
31,000 
120,755 
257,500 



13,900 
19,800 

IS, 300 

54,363 

31,000 

10,750 

6,300 

3,400 

10,100 

8, 175 
1.0,750 
L3.900 



:;. loo 



15,960 
56,053 
94,556 
105,555 
91,246 
18,852 
10,750 
5,000 

L8.948 

18,972 
15,789 

10,500 

41,073 



981,342 
3,113,026 
5,814,021 
6,280,959 
5,610,498 
1,121,771 
660,992 
340, so 5 
1,127,484 

1,160,5 13 

939,511 

2,490,801 

29,656,813 



0.76 
2.43 
4.53 
4.90 
4.39 
0.87 
0.52 
0.28 
0.88 
0.91 
0.73 
1 . 95 



23.15 



0.66 

2.33 
3.03 

4.39 

3.80 

0.78 
0.45 
. 24 
0.79 

o. ro 
0.66 
1.69 

1.71 



MARYLAND GEOLOGICAL SURVEY 



283 



Estimated Monthly Discharge of Susquehanna River at Harrisburg, 

Pennsylvania. 





DISCHARGE IN SECOND-FEET. 


TOTAL IN 
ACRE-FEET. 


RUN-OFF. 


MONTH. 


Maximum. 


Minimum. 


Mean. 


Depth in 
inches. 


Second-feet 

per square 

mile. 


1894 

January 

February 

March 

April 


56,338 

69,990 

179,725 

139,450 

454,900 

134,975 

19,300 

11,125 

63,775 

62,880 

99,375 

76,255 


17,250 
13,900 
25,025 
20 800 


26,921 
31,656 
70,347 


1,655,308 
1,758,084 

4,325,468 
3,948,337 
6,078, S4S 
2,995,438 
648,571 
426,416 
1,035,313 
1,590,991 
1,467,075 
2,156,370 


1.29 
1.37 
3.38 
3.07 
4.75 
2.34 
0.51 
0.33 
0.80 
1.25 
1.15 
1.68 


1.12 
1 .32 

2 . 93 
2 . 76 
4.11 
2.10 
0.44 
0.29 
0.72 
1.08 
1.03 
1.46 


May 


16 775 os'sfia 


June 


17,250 
6,900 
3,600 
3,000 
8,475 
18,300 
16,775 


50, 340 
10,548 
6,935 
17,399 
25,875 
24,655 
35,070 
38,747 


July 


August 

September 

November 

December 


The year. . 


454,900 


3,000 


28,086,219 


21 92 


1.61 


1895 

January 

February 

March 

April 


114,490 

87,790 

150,190 

206,575 

40,400 

29,100 

22,300 

9,125 

10,750 

4,500 

21,800 

63,775 


23,400 

21,800 

51,400 

29,100 

15,850 

5,400 

3,600 

3,400 

3,600 

2,200 

2,800 

5,400 


50,101 

54,026 

81,108 

85,979 

24,910 

11,315 

9,711 

5,402 

5,330 

3,152 

6,143 

18,990 


3,080,590 

3,000,452 

4,987,137 

5,116,106 

1,531,656 

673,289 

597,106 

332,156 

316,51', 2 

193,809 

365,534 

1,167,650 


2.41 
2.34 
3.89 
3.99 
1.20 
0.53 
0.46 
0.25 
0.24 
0.15 
0.29 
0.91 


2 . 09 
2.25 
3.37 
3.58 
1 . 04 
0.47 
0.40 
0.22 
0.22 
0.13 
0.26 
0.79 


May 


June 


July 

August 

November 


The year. . 


206,575 


2,200 


29,680 


21,362,047 


16.66 


1.24 


1896 

January 

February 

March . . 
April 


139,450 

185,990 

185,990 

223,580 

23,400 

46,825 

40,400 

45, 150 

7,850 

132,290 

143,030 

38,900 


23,400 

16,775 

16,775 

26,100 

7,825 

9,450 

10,750 

3,400 

3,000 

10,100 

12,700 

9, 125 


52.692 
52,637 
65,034 
89,469 
13,097 
19,387 
15,587 
14,621 
4,173 
34,793 
35,738 
21,573 


3,239,904 

3,027,715 

3,998,785 

5,323,776 

805,303 

1,153,607 

958,407 

899,009 

248,311 

2, 139,:;:; r 

2,126,559 
1,326,472 


2.53 
2 . 36 
3.13 
4.15 
0.63 
0.90 
0.75 
0.70 
0.19 
1.67 
1.66 
1.04 


2.19 
2.19 

2.71 
3 . 72 
0.55 
0.81 
0.65 
0.61 
0.17 
1.45 
1.49 
0.90 


May 

June 


July 

October 

November. . . . 
December 


The year. . 


223,580 


3,000 


34,900 


25,247,185 


19.71 


1.45 



2S4 



THE HYDROGRAPHY OF CECIL COUNTY 



The discharge of the Susquehanna River at Harrisburg, Pa., during 
1891-1900 is shown graphically in the following figures: 




Fig. 20. Discharge of Susquehanna River at Harrisburg, Pennsylvania, 1891-98. 



MARYLAND GEOLOGICAL SURVEY 



285 



Sec.-ft. ' " 

160,000 


JAN. 
10 20 


FEB. 

10 20 


MAR. 
10 20 


APR. 
10 20 


MAY 
10 20 


JUNE 
10 20 


JULY 

10 20 


AUG. 

10 20 


SEPT. 
10 20 


OCT. 

10 20 


NOV. 

10 20 


DEC 

10 20 


140,000 








o 
























































120,000 
































































100,000 










I 






















































80,000 


























































60,000 










' 




















































40,000 








F 








































l 








1 


20,000 1 


If 




\ 












































' 


1 






J 
















■ 


1 




























1*1 



Fig. 21. Discharge of the Susquehanna River at Harrisburg, Pa., during 1899. 



Sec.-ft, 

160 000 


JAN 
10 20 


FEB. 
10 20 


MAR 
10 20 


APR. 
10 20 


MAY 
10 20 


JUNE 
10 20 


JULY 
10 20 


AUG. 
10 20 


SEPT 
10 20 


OCT 
10 20 


NOV. 
10 20 


DEC 
10 20 


140,000 




% 




i 
























































O 

s 

- 






120 000 






































































100,000 








i 






















































80,000 
















1 




1 


















































60,000 














1 




| 
















































40,000 


1 


i 


1 


















































, 


i 


20,000 




m 


■ 












































I 




wmm 


1 


hi 


1 


i, 


m 


ht 


























| 


































Fig. 22. Discharge of the Susquehanna River at Harrisburg, Pa., during 1900. 



286 THE HYDROGRAPHY OF CECIL COUNTY 

Estimated Monthly Discharge of Susquehanna River at Harrisburg, Pa. 





DISCHARGE IN SECOND-FEET. 


TOTAL IN 
ACRE-FEET 


RUN-OFF. 


MONTH. 


Maximum. 


Minimum. 


Mean. 


Depth In 
Inches. 

0.91 
2.01 
4.30 
2.60 
2 . 60 
0.83 
0.56 
0.76 
0.32 
0.29 
0.69 
2.26 


Second-feet 

per square 

mile. 


1897 
Februarj' 


31,000 

103,850 

168,090 

132,290 

103,850 

29,100 

42,750 

40,400 

15,850 

11,900 

49,500 

108,275 


10,100 

23,400 

26,100 

25,025 

24,500 

10,100 

6,900 

7,825 

4,000 

4,000 

4,800 

18,300 


18,684 
46,304 
89,678 
56,021 
54,106 
17,926 
11,735 
15,738 
6,991 
6,127 
15,024 
47,068 


1,159,900 

2,571,590 

5,514,085 

3,333,480 

3,326,850 

1,066,680 

721,560 

967,690 

415,990 

376,730 

893,990 

2,894,100 

23,242,645 


0.79 
1.93 
3.73 
" 38 


May 


2 25 


July 


0.75 
49 


October 

November 


0.66 
0.29 
0.25 
0.62 
1.96 


The year. . 


168,090 


4,000 


32,132 


18.13 


1.34 



1898 

January 

February 

March 


150,190 

108,275 

242,375 

14 7,505 

87,790 

40,400 

15,000 

58,313 

23,400 

111,955 

118,965 

102,955 


13,100 

19,800 

27,225 

23,400 

35,400 

11,125 

5,250 

9,450 

5, 725 

5,250 

18,300 

13,100 


59,481 
52,435 
S9,331 
53,420 
59,701 
20,117 
8,499 
25,887 
11,657 
33,475 
40,848 
34,836 


3,657,368 

2,912,092 

5,492,785 

3,17S,704 

3,674,584 

1,197,042 

522,587 

1,591,740 

693,638 

2,058,311 

2,430,619 

2,141,996 

29,551,466 


2.86 
2.27 
4.29 
2.47 
2.87 
0.93 
0.40 
1.25 
0.55 
1.60 
1.90 
1.67 


2.4S 
2.18 
3.72 


May 


2 49 


June 


S4 


July 


o 35 


August 

September .... 


1 ,os 
0.49 
1.39 
1 . 70 
1.45 


The year. . 


242,375 


5,250 


40,812 


23.06 


1.70 


1899 
April 


105,450 

123,350 

194, '.15(1 

118,875 

54,435 

19,300 

11,900 

35,400 

12,700 

7,600 

4 2,800 

83,075 

194,050 


20,800 

13.100 

40,:;oo 

29,100 

IS, 300 

7,000 

5,675 

1,850 

5,0 50 

3,475 

11,1 25 

10,100 


44,350 

46,351 

102,511 

67,479 

25,263 

12,033 

8,349 

6,719 

0,010 

1,729 

19,019 
32,033 


2,726,975 
2,574,204 
6,303,155 
4,015,279 
1,553,361 
716,013 
513,360 

n:;,i35 

411,709 

200,;;:, 

1,181,709 

1,969,632 


1 . 85 
1.93 

4.27 
2.81 
1.05 
0.50 
0.35 
0.28 
0.29 
0.20 
0.79 
1.3:; 


3.18 

2.01 
4 . 92 
;; L8 


May 


l 21 


•i nne 


56 


July 

August 

September 

October 

November .... 


O. Ill 

0.32 
0.82 

0.23 

0.88 

l .5:; 


The year. . 


3, 175 


31,313 


22,619,307. 


1 .30 


1 7 . 04 



MARYLAND GEOLOGICAL SURVEY 287 

Estimated Monthly Discharge of Susquehanna River at Harrisburg, Pa. 





DISCHARGE IN SECOND-FEET. 


TOTAL IN 
ACRE-FEET. 


RUN-OFF. 


MONTH. 


Maximum. 


Minimum. 


Mean. 


Depth in 
Inches. 


Second-feet 

per square 

mile. 


1900 
April 


177,050 
161,835 
196,740 

93,815 

35,400 

19,800 

10,100 

10,100 

7,830 

8,475 

195,845 

94,710 


11,125 

12,700 

23,400 

35,400 

13,100 

7,830 

5,475 

3,035 

2,364 

2,670 

4,430 

13,900 


57,339 

64,337 

68,044 

58,380 

19,466 

13,629 

7,550 

5,394 

3,931 

4,554 

34,005 

37,041 

30,397 


3,518,874 

3,573,095 

4,183,862 

3,473,853 

1,196,917 

810,983 

464,231 

331,664 

333,911 

280,015 

1,438,397 

3,377,563 


2.75 
2.79 
3.27 
3.71 
0.93 
0.64 
36 
0.35 
0.18 
0.22 
1.12 
1.78 


2.38 
2.68 
3.83 
2.43 


May 


0.81 




0.57 


July 


0.31 


September .... 


0.32 
0.16 
0.19 
1.00 
1.54 


The year. . 


196,740 


2,364 


21,773,362 


17.00 


1.26 



Measurements of flow of a number of the chief tributaries of the 
Susquehanna have also been made by the IT. S. Geological Survey. 
North Branch has been systematically measured at Wilkesbarre and 
at Danville, Pennsylvania, and the West Branch at Allenwood, Penn- 
sylvania. The "Wilkesbarre station was established March 30, 1897, 
and the Danville and Allenwood stations, March 25, 1899. Juniata 
river, which rises in Center county, Pennsylvania, and flows into the 
Susquehanna about 15 miles above Harrisburg, has been measured 
since March 21, 1899, at Newport, about 15 miles above the junc- 
tion of the river with the Susquehanna. 



THE MAGNETIC DECLINATION IN CECIL 

COUNTY 

BY 

L. A. BAUER 



Magnetic observations for the purpose of determining the magnetic 
declination of the needle, or the " variation of the compass," have 
been made by the Maryland Geological Survey and the United States 
Coast and Geodetic Survey at the following points within the 
county. 

TABLE I 
Magnetic Declinations Observed in Cecil County. 









Magnetic 




No. 


Station. 


Latitude. 


Longitude Date of 
Gr'nwich. Observation. 


Declination on 


Observer. 


Re- 




Date Jan. 1,1900 




marks. 










west west 






1 


Elkton,near 








Sur- 




S.M.stone. 


39°36'.5 


79°49'.5 Oct. 15, 1896 5°12'.0 5°21'.6 


L. A. Bauer should 


2 


Elkton,atS. 






use 




M. stone. . 


39 36 .5 


79 49 .5 June 9, 1900 5 21 .3 20 .0 


J. B. Baylor r m 








Mean 5 21 




stone 


3 


Elkton.atN. 












M. stone. . 


39 36 .5 


79 49 .5 June 9, 1900 5 51 .5 5 50 


J. B. Baylor 


4 


Rising Sun. 


39 41 .5 


76 03 .3 June 22, 1899 5 08 .8 5 10 "1 
75 57 .7 June 22, 1899 5 26 .0 5 28 / 


L. A. Bauer & 


5 


Calvert .... 


39 41 .8 


J. A. Fleming! 



All values refer to mean of day (24 hours.) 

DESCRIPTION OF STATIONS. 
1. — Elkton. Near South Meridian Stone, High School Grounds. 

2. " At South Meridian Stone, High School Grounds. 

3. " At North Meridian Stone, High School Grounds. 

4. — Rising Sun. In Mr. H. J. Briscoe's Held near the north corner of fence, and 

east of railroad station. 
5. — Calvert. Near southeast corner of school lot, about in line with east edge of 

school and 16 paces north of large oak. 

For a description of the methods and instruments used, refer- 
ence must be made to the " First Report upon Magnetic Work 
in Maryland," vol. i, Maryland Geological Survey Report. This 
report gives likewise an historical account of the phenomena of the 
compass-needle and discusses fully the difficulties encountered by 

19 



290 THE MAGNETIC DECLINATION IN CECIL COUNTY 

the surveyor on account of the many fluctuations to which the 
compass-needle is subject. Surveyors of the county desiring a copy 
of this report should address the State Geologist. 

Mekidian Line. 

On June 8, 1900, Mr. J. B. Baylor, acting under instructions of 
the Superintendent of the United States Coast and Geodetic Survey 
as issued to him, in response to a request from the State Geologist, 
established a true meridian line at Elkton, in the High School 
grounds. This line is marked by two substantial monuments, suit- 
ably lettered and firmly planted in the ground. 

The South Stone was placed within a few feet of the magnetic 
station of 1896 and is 36 feet from the west fence around the High 
School grounds, and 34.5 feet from the south fence. The North 
monument is about 270 feet due north, and is 30 feet from the west 
fence of the school grounds and 11 feet from the north fence. The 
soil is a mixture of black loam and gravel. 

The South Stone being well removed from all disturbing 
influences, should be the one to be used by surveyors when 
making their tests. 

The magnetic declination (variation of the compass) reduced to 
its average value for the day (24 hours) was found by Mr. Baylor to 
be at the South Stone, June 9, 1900, 5° 21'.3 West. 

Within a few feet of this place Mr. L. A. Bauer, on October 12, 
1896, obtained 5° 12'. West, showing that the north end of the 
magnetic needle is at the present time moving about 3' per annum 
wcstwardly. 

Mr. Baylor found the magnetic declination to be at the North 
Stone, June 9, 1900, 5° 50'. 5 West, showing the necessity for sur- 
veyors, making their tests over the same stone and, for reasons stated 
above, over the South Stone. 

to obtain the mean value of the magnetic declination at the 
South Stone for any subsequent time, within the next ten years, 
add to 5° 21' an amount at the bate of 3' per annum fob the 

TIME ELAPSED SINCE Ja.XI'AKV 1, 1900. 



MARYLAND GEOLOGICAL SURVEY 291 

When the surveyor determines the value of the magnetic declina- 
tion, it would be well for him to make the observations on several 
days, if possible. Probably the best time of day for making the 
observations would be towards evening, about 5 or 6 o'clock. 1 At 
this time the declination reaches, approximately, its mean value for 
the day (see Table II). The observations on any one day should 
extend over at least one-half of an hour, preferably an hour, and 
the readings should be taken every ten minutes. Before each 
reading of the needle it would be well to tap 2 the plate lightly with 
the finger or a pencil so as to slightly disturb the needle from the 
position of rest it may have assumed. The accurate time should be 
noted opposite each reading and a note entered in the record-book 
as to the date, the weather and the kind of time the observer's watch 
was keeping. It is very essential that the surveyor should have 
some knowledge as to the error s of his compass. He can determine 
this by making observations as stated at the South Meridian Stone. 
He should reduce the value of 5° 21' to the date of his tests, and 
the difference between this value and his own will be his compass 
error. 

If the surveyor has an instrument which admits of the refinement 
to take into account the change in the magnetic declination during 
the day, he may use the following table to correct his readings: 

To reduce an observation of the magnetic declination to the mean 
value for the day of 24 hours, apply the quantities given in the table 
below with the sign as affixed: 

1 Or the surveyor may make bis observations in the morning and early in the after- 
noon, at about the time of minimum and maximum values of the magnetic declina- 
tion. He may regard the mean of the two extreme values as corresponding closely 
to the mean value for the day (24 hours). 

2 Great care must be taken not to electrify the needle by rubbing the glass plate in 
any manner. Remarkable deflections of the needle can thus be produced. 

3 1 have found surveyors' compasses to differ at times as much as 1° from the 
readings with the Coast and Geodetic Survey Standard Magnetometer. The error 
may be due to a variety of causes, such as an imperfect pivot, non-coincidence of 
magnetic axis of needle with the geometric axis, and loss of magnetism of the 
needle. 



292 



THE MAGNETIC DECLINATION IN CECIL COUNTY 



TABLE II. 



Mouth. 


6 


7 


8 


9 


10 


11 




o 




1 


■2 3 


4 


5 


6 




A.M. 








2; 






/ 




P.M. 




/ / 


/ 


/ / 


/ 


/ 


/ 


/ / 


/ 


/ 




— 0.1 +0.3 +1.0 


+ 3.1 +3.4 


+ 1.3-1.1 


-2.5 


-3.6-3.1 


-1.3 


-0.3 


+ 0.3 


February . ... 


+ 0.6 +0.7 +1.5 


+ 1.9 +1.4-0.1 -1.5 


-2.1 


-3.5-2.0 


-1.3 


-0.8 


-0.4 




+ 1.2 +3.0 +3.0 


+ 2.8+1.6—0.6—2.5 


-3.4—3.7-3.3 


—2.3 


-1.3 


-0.5 




+ 3.5 +3.1 +3.4 


+ 3.0 +0.8-3.1-4.0 


-4.1-4.3-3.6 


-2.3 


-1.3 


-0.3 


May 


+ 3.0 +3.8 +3.9 


+ 3.0+0.l!-2.4[-4.0 


-5.0-4.5-3.6 


— 3.3 


-0.9 


+ 0.1 




+ 3.0 + 4.4 +4.4 +3.3+1.1— 2.0 -3.6 


-4.5— 4.5-3.S 


— 2.6 


-1.3 


-0.2 


July 


+ 3.1 +4.(5 +4.9+3.9+1.8—1.2—3.4 


-4.4 


— 4.7-4.3 


-2.S 


-1.3 


— 0.3 




+ 3.0 +4.9 +5.4 +3.7 +0.4— 2.8-4.7 


-5.1 


— 4.9-3.7 


-1.9 


— 0.6 


+ 0.3 


September. . . . 


+ 1.S +3.8 +3.4 


+ 2.5 


+ 0-3 


-3.7 


-4.4 


-4.6 


-4.3-4.0 


-1.4 


-0.3 


-0.1 


October 


+ 0.5 +1.6 


+ 3.1 


+ 3.8 


+ 1.4 


-1.0 


-3.7 


-3.3 


-3.4-2.4 


-1.3 


-0.4 


-0.4 


November .... 


+ 0.5+1.3 


+ 1.7 


+ 1.8 


+ 1.1 


-0.5 


-2.0 


-3.7 


-2.6-1.8 


-1.0 


-0.3 


+ 0.2 


December .... 


+ 0.3 +0.3 


+ 0.8 


+ 1.8 


+ 1.8 


0.0 


-1.6 


-3.4 


-2.3 -l.s 


-1.1 


-0.3 


+ 0.1 



This table shows that during August, for example, the magnetic 
declination has its lowest value about 8 a. m. and its highest value at 
about 1 p. m., and that between these two hours the needle changes 
its direction about 10', which amounts to 15 feet per mile. In 
winter the change is considerably less. 

Table III shows how the magnetic declination has changed at 
Elkton between 1700 and 1900. 



TABLE III. 



Year 


Needle 


Year 


Needle 


Year 


Needle 


Year 


Needle 


Jan. 1. 


pointed. 


Jan. 1. 


pointed. 


Jan. 1. 


pointed. 


Jan. 1. 


pointed. 


1700 


5°30'W 


1750 


2°30'W 


1800 


0°02'W 


1850 


2°01'W 


10 


5 05 


60 


1 44 


10 


07 


60 


3 43 


30 


4 34 


70 


1 05 


20 


34 


70 


3 34 


30 


3 58 


80 


31 


30 


50 


80 


4 09 


40 


:; 17 


90 


12 


40 


1 25 


00 


4 50 


50 


2 30 W 


1800 


03 W 


50 


2 01 W 


1900 


5 31 W 



From this table it will be noticed that the needle is at the present 
time pointing about the same amount to the west that it did two 
centuries ago, and that in about 1800 the magnetic declination was 
practically zero, that is, the magnetic needle pointed exactly to the 
true north pole. What the change of 5^° in a century in the point- 
ing of a magnetic needle implies may be readily understood from the 
following statement: 



MARYLAND GEOLOGICAL SURVEY 293 

A street a mile long, laid out in Elhton in 1800 to run north and 
south by the compass, would, at the present time, have its north 
terminus about 1/10 of a mile too far east! 

The above figures enable the surveyor to ascertain the precise 
amount of change of the magnetic declination or pointing of the 
compass between any two dates between 1700 and 1900. It should 
be emphasized, however, that when applying the quantities thus 
found in the re-running of old lines, the surveyor should not forget 
that the table cannot attempt to give the correction to be allowed on 
account of the error of the compass used in the original survey. 

In conclusion, it should be pointed out that local disturbances of 
the compass are quite frequent in this region of Maryland, and that 
on this account it is not possible to draw for the county the lines of 
equal magnetic declination, without the aid of many more observa- 
tions than contained in Table I. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XXIV. 




CHARCOAL BURNERS CAMP. 



THE FORESTS OF CECIL COUNTY 

BY 

H. M. CURRAN. 
With an Introduction by George B. Sudworth 



INTRODUCTION. 



The following report on the " Forests of Cecil County " is made 
under the auspices of the Bureau of Forestry in cooperation with the 
Maryland State Geological Survey. This cooperation dates from 
1900, when the Division of Forestry furnished a report on the " For- 
ests of Allegany County." It is gratifying to state in this connection 
that, with its greater force of assistants, the Bureau of Forestry has 
been able to carry on a much larger amount of forest work in Mary- 
land during the season of 1901 than was previously possible. Follow- 
ing Allegany county, three of the best wooded counties of the State 
were thoroughly explored; these comprise Cecil, Garrett, and Calvert 
counties. As planned by Professor Clark, each of these reports will 
be published separately. 

Mr. H. M. Curran, Agent in the Bureau of Forestry, Division of 
Forest Investigation, has efficiently prosecuted this work. He was 
assisted in making valuation surveys of the various types of forests 
by Messrs. J. E. Keach, A. O. Waha, and F. R. Miller. Special 
credit is due, also, to Mr. John Foley, of the Division of Forest 
Management, for the excellent photographs from which half-tone 
illustrations were made for the Cecil, Garrett, and Calvert county 
reports. 

Acknowledgments are due the Kenmore Pulp and Paper Com- 
pany, of Elkton, and the Prineipio Forge Company, at Principio Fur- 



296 



THE FORESTS OF CECIL COUNTY 



nace, for their courtesy in furnishing information in regard to the 
manufacture of pulpwood and charcoal. 

The Maryland Geological Survey bore the expenses of all the field 
work and travel connected with these investigations, while the Bureau 
of Forestry contributed the services of the necessary experts. 

The purpose of these investigations is to give a comprehensive view 
of the forest resources of the counties named and finally of the entire 
State. The scope of the work includes a study of available timber 
supplies, their character, extent, and relationship to dependent wood- 
consuming industries, and of causes which have deteriorated the 
quality and greatly depleted Maryland forests. While the space and 
time devoted to this report would not permit the presentation of a 
technical working plan applicable to the various types of forests 
studied, yet a special effort has been made to point out the abuses and 
neglect to which the forests have long been subjected. Emphasis has 
been laid also upon the necessity and importance of a conservative 
management and improvement of existing woodlots and timber tracts. 
To this end the author has given some general instructions whick, if 
followed, it is believed would prove widely beneficial in the improve- 
ment, extension, and maintenance of a more regular supply of com- 
mercial and other timber. In addition to observing these general 
precautions, the owners of woodlots and timber tracts may avail them- 
selves of the expert advice and cooperation 1 offered by the Bureau 
of Forestry both in tree planting and in the conservative management 
of woodlands and timberlands. 

Location. 
Cecil is the most northern of the Eastern Shore counties of Mary- 
land. It is situated at the head of Chesapeake Bay, which forms 
part of its southern boundary. The Susquehanna river is the western 
boundary and separates Cecil from Harford. On the north and east 
the county is bounded by Pennsylvania and Delaware. 

1 Outlined in Circulars 21 and 22, copies of which may he had gratis by applying to 
the Bureau of Forestry, U. S. Department of Agriculture, Washington, D. C. 



MARYLAND GEOLOGICAL SURVEY 



CECIL COUNTY, PLATE XXV 




MARYLAND GEOLOGICAL SURVEY 297 



Topography and Soil. 



The most marked topographic features of Cecil county are the 
broad necks of land separated by tidal rivers (Plate XXII). These 
necks are found in the southern part of the county and often bear 
the name of the adjacent river. The principal necks, beginning- at 
the south, are, Sassafras, Middle, Town Point, Back Creek, and Elk. 
Sassafras and Elk are the largest necks, being 12 miles long. The 
greatest width of Sassafras Neck is seven miles, and of Elk, five. 

With the exception of Elk Neck, these divisions are level or roll- 
ing areas of clayey or sandy loam, as shown in Plate XXII, Pig. 2. 
Their general elevation above tide-water is never more than 80 feet. 
They slope gradually to the bay-shore or end abruptly there in steep 
cliffs. 

Elk Neck differs from the other necks in having a ridge or back- 
bone of high land for the greater part of its length (Plate XXII, 
Fig. 1). The high points of this ridge reach an elevation of 300 
feet. Its soil, too, varies with its topography, being poor, rocky, or 
of a gravelly nature, especially in the north. The slopes along the 
bay-shore are good farming lands, though hardly equalling in fer- 
tility the deep soils of the eastern necks. 

The northern and main portion of the county reaches an elevation 
of 400 feet for the greater part of its area. The lower half is 
broken and hilly, with poor gravel soils similar to those of Elk Neck. 
North of this is a belt of good soil from three to five miles wide ex- 
tending across the county from east to west. This section is rolling, 
with its lowest depressions along the streams, and ends abruptly to 
the west in steep cliffs along the Susquehanna river. 

Drainage. 

Chesapeake Bay receives the entire drainage of the county through 
numerous sluggish streams in the south and through swift-flowing, 
shallow creeks (Plate XXIII, Pig. 2) in the north. The creeks are 
from 30 to 100 feet in width and usually carry less than two feet of 
water. 



298 THE FORESTS OF CECIL COUNTY 

In the southern part of the county wide tidal rivers (Plate XXIII, 
Fig. 1) receive the water from the creeks and form waterways for 
the Bay shipping. The principal rivers of the county are, Northeast, 
Elk, Bohemia, and Sassafras. Their greatest width is two miles, and 
all have ship channels. The Susquehanna river, receiving the drain- 
age of the western portion of the county, enters the Chesapeake at 
Perryville. 

"Woodlands and Forests. 

The total area of Cecil county is 375 square miles, or 240,000 
acres. The area of the included water (ponds, rivers, etc.) is 10,300 
acres, and of the marsh, 3600 acres. This leaves for the farm-lands 
and forest 226,100 acres. The wooded portion of the county is 15 
per cent of this, or 35,000 acres. 

Forest Types. 

The wooded areas comprise two types of forest. The first type 
(Plate XXYI) — Barrens limber — is found on the poor gravel soils 
of Elk Neck, and on similar soils of the region north and east. It is 
a young hardwood growth, with areas on which Scrub Pine occurs. 
The second type (Plate XXVII) — Shore Timber — includes the thin 
fringe of trees found along the streams, rivers and bay-shore. The 
growth is mainly hardwood, of both mature and young trees. 

BARRENS TIMBER. 

This type of forest has an area of 20,000 acres, distributed as 
shown on the map (Plate XXV), and covers the region locally 
known as " Barrens." The term " Barrens " is applied to this re- 
gion because of the poor soil found there and the fact that large 
areas are constantly covered with brush (Plate XXVI, Fig. 2). 
When fire kills this brush, the burned areas are indeed barren. 
The timber of the Barrens is not virgin, but a sprout growth of 
Chestnut and Oak. In age it varies from one to forty years. The 
periodical removal, by the charcoal-burner, of all sound material one 
inch and over in diameter has resulted in rather even-aeed stands of 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XXVI. 





MARYLAND GEOLOGICAL SURVEY 299 

Chestnut and Oak, which sprout readily. In regions where fires 
occur the stands are very thin and open (Plate XXVI, Fig. 1), allow- 
ing Scrub Pine and Mountain Laurel to come in. 

The character of this timber is shown in the following' table: 

TABLE SHOWING RELATIVE ABUNDANCE OF SPECIES IN THE BARRENS 

TIMBER. 

Average of 43 acres. Trees 5 inches and over in diameter breast high. 

Average Average 
Average Percentage diameter stand 

number of of each breast high. per acre. 

Species. trees per acre. species. Inches. Cords. 

Red and Black Oaks 49 31 12 2.56 

Chestnut 36 23 10 2.10 

White Oaks 30 19 10 .94 

Chestnut Oak 22 14 8 .60 

Tulip-tree . . 

Other species 21 13 9 .85 

Average of all species 158 10.3 100 7.05 

NOTE. 
Red and Black Oaks 

include: Red, Scarlet, Yellow, Spanish, Pin, Black Jack, Willow, and 

Bartram Oaks. 
White Oaks 

include : White and Post Oaks. 
Other species 

include : Red Cedar, Scrub Pine, Mockernut and Pignut Hickories, 
Locust, Beech, Red Maple, Lar^etooth Aspen, Black Gum, 
Sweet Gum, Dogwood, Sassafras, Mountain Laurel, and Blue 
Beech. 

The total stand on the 20,000 acres of the Barrens is 111,000 
cords. Most of the wood cut here is made into charcoal. A cord of 
wood properly burned yields 25 bushels of coal; so that, reduced to 
the charcoal burner's unit, the total yield would be 3,525,000 bushels. 
This amount of coal can be made from the Barrens timber, but the 
thinness of the stands over the greater part of the area so increases 
the cost of hauling and cutting as to make the work unprofitable. 
The thinness of the stands is due to fire, and the fires are due to 
carelessness. The normal wood production for the Barrens is in the 
neighborhood of 30 cords per acre. Burnt areas yield less than ton 
cords per acre. The difference, 20 cords, worth $1.00 per cord, 
represents the loss per acre from fire. The burning of 100 acres of 



300 THE FORESTS OF CECIL COUNTY 

fully-stocked brush lands means a loss to the owner of from $1600 
to $2000. 

SHORE TIMBER. 

This second type of forest has an area of 15,000 acres distributed 
as indicated on Plate XXV. It occupies the depressions along the 
streams, or occurs as thin fringes on the bay-shore (Plate XXVII). 
The greater part of this shore-timber is found in the best agri- 
cultural regions of the county, and the soils upon which it grows 
are often similar to those of the surrounding farm-lands. The fact 
that these timbered areas are at certain seasons too wet for grain 
crops, or so steep that they gully when under cultivation, accounts 
for their remaining in forest. These forests, mainly hardwoods, 
have been constantly culled by the farmers and others for all kinds 
of material for domestic use and for sale. We find here defective 
old Oaks and Chestnuts (Plate XXVIII, Fig. 1), remnants of the 
virgin forest, and associated with them, sprouts and seedlings of many 
species. The sides of the depressions and the moist bottoms, where 
the drainage is good, are capable of supporting a very vigorous tree 
growth (Plate XXVIII, Fig. 2). Chestnut and White Oak do well 
on the slopes, while Tulip-tree and Black Walnut thrive nearer the 
streams. The growth of all these species is especially good in the 
southern part of the county, where the greater part of the shore- 
timber is found; the streams in the north (Plate XXIII, Fig. 2) have 
little or no timber along their courses. 

The varied character of this type and its distribution over the 
county in small patches make the cost of gathering sufficient meas- 
urements for an estimate of the present stand, prohibitive. The fol- 
lowing table is the result of the measurement of a number of the 
better stands (Plate XXVII, Fig. 1) and may not be applied to the 
15,000 acres of the type. 



Maryland GEOLOGICAL SURVEY. 



Cecil county, plate xxvl 




Fro. 1.— A GOOD STAND, SASSAFRAS NECK. 




FlO. 2.— INTERIOR VIEW OF Al'.OVE. 



SHORE TIMBER. 



MARYLAND GEOLOGICAL SURVEY 301 

TABLE SHOWING THE RELATIVE ABUNDANCE OF DIFFERENT SPECIES 

IN THE SHORE TIMBER, 

Average of 32 acres. Trees 5 inches and over in diameter breast high. 

Average Average 
Average Percentage diameter stand 

number of of each breast high. per acre 

Species. trees per acre. species. Inches. Cords. 

Chestnut 24 18 14 8.64 

Red and Black Oaks 18 14 15 2.76 

Chestnut Oak 10 8 16 2.04 

White Oaks 8 6 17 1.81 

Tulip-tree 8 6 14 .81 

Other species 65 48 11 3.93 

Average of all species 133 100 13 14.09 

NOTE. 
Red and Black Oaks 

include : Red, Scarlet, Yellow, Spanish, Pin, Black Jack, Willow, and 
Bartram Oaks. 
White Oaks 

include: White, Post, Swamp White, and Cow Oaks. 
Other species 

include : Red Cedar, Pitch Pine, Scrub Pine, Black Cherry, Mockernut, 
Pignut and Bitternut Hickories, Basswood, Locust, Beech- 
Sycamore, River Birch, Red Maple, Black Gum, Sweet Gum, 
White Willow, Red Mulberry, Persimmon, Butternut, Dog- 
wood, Sassafras, Laurel, Blue Beech, and Redbud. 

The grouping of commercial trees with inferior species in the tables 
is due to the fact that they occur in such small numbers on the areas 
measured as to be of little importance. 

The above table shows an average of 15 cords per acre for the 
better stands. If this wood were of a quality to make lumber, the 
yield would be 12,000 board feet per acre. Little lumber is ever 
cut from these stands, as most of the good material is cut before it 
reaches timber dimension. The material left year after year to 
grow to large size (Plate XXVIII, Fig. 1) is usually defective and 
unfit for lumber. 

The table also shows the effects of culling. The inferior species 
in the stands measured are 48 per cent of the total number of trees. 
The constant removal of the Oaks, Chestnut, and Tulip-tree, and the 
leaving of other species results in an ever-increasing proportion of 
what may be termed the weeds of the forest. When the best stands 
show 48 per cent of weeds, one may expect the poor stands to show 



302 THE FORESTS OF CECIL COUNTY 

even a larger proportion. In many observed cases the entire stand 
is weed growth. In the forest, as on the farm, knowledge and in- 
dustry bring good crops; ignorance and neglect, weeds. 

The shore woodlands are well adapted to the growth of trees suit- 
able for lumber. The land, though unsuited to agriculture, is well 
suited to tree growth. The principal commercial trees, Oaks, Chest- 
nut, Tulip-tree, Black Walnut, Hickory, and Ash grow rapidly and 
reach large sizes when properly treated. Cheap water transporta- 
tion to the principal eastern markets, New York, Philadelphia, and 
Baltimore, as well as to the local markets in the county, is possible. 
The large farming population could be employed in the winter, when 
work is slack, to cut and manufacture the product. The fire danger 
is small, owing to the position of the timber, with cultivated land on 
( >ne side and water on the other. Taxes, though high, are being paid 
by the owners on lands producing poor wood crops, and the rates would 
not be increased if full crops of good material were produced. 
Every condition is favorable to the profitable production of forest 
crops on the shore woodlands. The future should see every acre of 
the 15,000 in this type producing at least 12,000 feet of lumber, the 
equivalent of the 15 cords of wood found on the best stands to-day. 
This would mean ISO million feet of lumber for the shore-timber, 
an amount far below its producing capacity. 

Forest Trees. 

The trees found in the county are principally hardwoods. Bed 
Cedar and Pitch, Shortleaf and Scrub Pines are the only conifers 
found, and only two, Bed Cedar and Scrub Pine, are common. The 
mingling of northern and southern species in this locality accounts 
for the large number present. The following is a list of the native 
trees of Cecil county: 

CONIFERS. 

1 Pitch Pine Pinus rigida. 

2 Scrub Pine Pinus virginiana. 

3 Shortleaf Pine Pinus echinata. 

4 Red Cedar Tuniperus virginiana. 



MARYLAND GEOLOGICAL SURVEY 303 

HARDWOODS. 

5 Butternut Juglans cinerea. 

6 Black Walnut Juglans nigra. 

7 Bitternut Hickory Hicoria minima. 

8 Mockernut Hickory Hicoria alba. 

9 Pignut Hickory Hicoria glabra. 

10 White Willow Salix alba. 

11 Largetootk Aspen Populus grandidentata. 

12 River Birch Betula nigra. 

13 Sweet Birch Betula lenta. 

14 Blue Beech Carpinus caroliniana. 

15 Beech Fagus atropunicea. 

16 Chestnut Gastanea dentata. 

17 White Oak Quercus alba. 

18 Post Oak Quercus minor. 

19 Chestnut Oak Quercus prinus. 

20 Swamp White Oak Quercus platanoides. 

21 Cow Oak Quercus michauxii. 

22 Red Oak Quercus rubra 

28 Scarlet Oak Quercus coccinea. 

24 Yellow Oak Quercus velutina. 

25 Spanish Oak .... Quercus dig it at a. 

26 Pin Oak Quercus palustris. 

27 Black Jack Oak Quercus marilandica. 

28 Willow Oak Quercus phellos. 

29 Bartram Oak Quercus heterophylla. 

30 Slippery Elm Ulmus pubescens. 

31 White Elm Ulmus americana. 

32 Hackberry Celtis occidentalis. 

33 Red Mulberry Morus rubra. 

34 Sweet Magnolia Magnolia glauca. 

35 Tulip-tree Liriodendron tulipifera. 

36 Papaw Asimina triloba. 

37 Sassafras Sassafras sassafras. 

38 Witch Hazel Hamamelis virginiana. 

89 Sweet Gum Liquidambar styraciflua. 

40 Sycamore Platanus occidentalis. 

41 Serviceberry Amelanchier canadensis. 

42 Scarlet Haw ■ Crataegus coccinea. 

43 Black Cherry Primus serotina. 

44 Redbud Cercis canadensis. 

45 Honey Locust Qleditsia triacanthos. 

46 Locust Robinia pseudacacia. 

47 Ailanthus Ailanthus glandulosa. 

48 Staghorn Sumach Rhus hirta. 

49 Holly Ilex opaca. 

50 Silver Maple Acer saccharinum. 

51 Red Maple Acer rubrum. 



304 THE FORESTS OF CECIL COUNTY 

Hahdwoods — Continued. 

52 Boxelder leer negundo. 

58 Basswood Tilia americcma. 

54 Dogwood ( 'ornus florida. 

55 Black Gum Nyssa sylvatica. 

56 MountaiD Laurel. . Kalmia latifolia. 

57 Persimmon .Diospyros virginiana. 

58 Black Ash Fraxinus nigra. 

59 White Ash Fraxinus americana. 

60 Red Ash . Fraxinus /ic/uixi/trtniirn. 

61 Nanuyberry . Viburnum prunifolium. 

Distribution. 
The trees of Cecil county may be arranged in two groups, based 
on their commercial importance and their abundance. 
I. — Important Commercial Trees. 
II. — Inferior Commercial Trees. 
The first group contains those species which furnish lumber, posts, 
ties, or telegraph poles. The second group consists of those species 
which yield cordwood. 

IMPORTANT COMMERCIAL TREES. 

The abundant trees of this group are Chestnut, Tulip-tree (Yellow 
or White Poplar), and White, Red, and Black Oaks. They are found 
in all parts of the county in varying quantities. The tables on pages 
299 and 301, based on a careful measurement of seventy-five acres 
of the two types of forest, show the abundance of the species, the 
relative proportion of each, and their average diameter. Under 
White Oaks are included White, Post, and Swamp White Oaks. 
Chestnut Oak has been separated from the other White Oaks be- 
cause it furnishes tan-bark. The Black and Red Oaks comprise the 
remaining species of Oaks found in the county. 

Chestnut predominates on the better soil of the shore-timber, while 
in the Barrens Red and Black Oaks are the most abundant species. 
The shore-timber has 52 per cent of commercially important trees 
and the Barrens 87 per cent. Tulip-tree is not found in measurable 
quantities on the poor soil of the Barrens, but is uniformly distributed 
through the moister shore woodlands, which are especially adapted 
to its growth. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XXVIII. 





MARYLAND GEOLOGICAL SURVEY 305 

Black Walnut, Black Cherry (Plate XXIX, Fig. 1), White Ash, 
Red, Ash, Beech, Basswood, the Elms, and the Hickories, which 
are present over the greater part of the county, reach large sizes, and 
would, if properly grown, produce merchantable timber. Black 
Walnut is especially at home in the moist bottoms along the streams. 

The three pines of the county, Pitch, Scrub, and Shortleaf, are 
found in greatest numbers on Elk Neck. The Pitch and Shortleaf 
Pines occur only as scattered individuals, while the Scrub Pine forms 
pure stands (Plate XXIX, Pig. 2) on areas once cultivated. Red 
Cedar is found in all parts of the county as a tree of fence rows 
(Plate XXIX, Fig. 1) and is a distinct feature of the agricultural 
regions. 

Locust, with Red Cedar and Sumach, occurs as a roadside tree and 
is also associated with these and Scrub Pine on areas formerly culti- 
vated. On good soil Locust is a rapid grower, and, if in the open, 
soon reaches a size suitable for posts. 

INFERIOR COMMERCIAL TREES. 

The abundant species of this group are, Sweet Gum, Black Gum, 
Red Maple, Persimmon, Dogwood, Sassafras (Plate XXX, Fig. 1), 
Sycamore, River Birch, Red Mulberry, Willow, Blue Beech, Laurel, 
Staghorn Sumach, and Witch Hazel. They are common in all parts 
of the county, but never form pure growth. They occur as scat- 
tered individuals in the forest, or form clumps or fringes (Plate 
XXIII, Fig. 2) along the streams. 

The less abundant species of the group are, Sweet Birch, Black 
Ash, Silver Maple, Boxelder, Holly, Papaw, Honey Locust, Red- 
bud, Hackberry, Serviceberry, Xannyberry, Ailanthus, Butternut, 
Aspen, Sweet Magnolia, and Scarlet Haw. These species, though 
not found throughout the county, are often quite common in certain 
localities. 

Use of Material. 

The principal uses of wood in the county are for charcoal, building 
material, pulpwood, ties, telegraph poles, fencing, and firewood. The 

20 



300 



THE FORESTS OF CECIL COUNTY 



local demand for these products, with the possible exception of char- 
coal and firewood, is greater than the supply. 



BUILDING MATERIAL. 



Only a small portion of the lumber used for building in Cecil 
county is manufactured there. The absence of timber suitable for 
lumber is very noticeable and is emphasized by the fact that there 




Fig. 23. Cordwood for pulp. Elkton. 

is not a sawmill of any size operating in the county. Even portable 
mills are very rare, and can tind work for only a few months in the 
year. Although the population of Cecil county is large and thrifty, 
and the demand for Lumber constant/no attempt is being made to 
increase the local supply of timber. 



PULPWOOD. 



The Large pulp mill at Elkton (Fig. 23) consumes annually 12,000 
cords of wood, but can obtain only a small amount of it in the county. 



MARYLAND GEOLOGICAL SURVEY 307 

The wood of the Tulip-tree (called "White Poplar) is the principal 
pulp material used by the mill. jSTo attempt is being made to grow 
wood for this industry. The present treatment of the Tulip-tree in 
Cecil county will decrease rather than increase the future supply. 
The trees are cut. when they have reached a diameter of 6 or S 
inches (Plate XXVIII, Pig-. 2). The cutting usually takes place in 
the spring or early summer, when the bark is easily removed. Stumps 
cut at this season often refuse to sprout or the stumps decay so rap- 
idly as to make the sprouts unthrifty or short-lived. Very often 
thick stands of young Tulip-trees are cut and every tree removed. 
When the stumps fail to sprout a second crop is lost, as no seed trees 
have been left. 

TIES AND TELEGKArH POLES. 

Most of the timber used for these purposes is Oak or Chestnut. 
Telegraph poles are made from Chestnut, while both Chestnut and 
Oak are used for railroad ties. The "White Oaks are preferred by 
the tie-makers, but the Red and Black Oaks are often used. There 
is always a good market for ties and poles in the county and fair 
prices are paid. Parmers owning stands of younk Oak and Chest- 
nut often sell them to contractors. A given price per tie or pole is 
paid or the stand is sold as a whole and the contractors cut what they 
can from it. This method of disposing of the timber is seldom saiis- 
factory to the farmers, because they are not well-informed as to 
what a given tract will yield, or what the materials are worth. They 
are thus the prey of unscrupulous contractors. 

FENCING. 

Farmers have for some time been troubled by the gradual disap- 
pearance of fencing material. The use of hedges and wire has les- 
sened the demand for Chestnut, the principal material for rails. This 
material is still plentiful, owing to the rapid growth of the Chestnut 
from sprouts, and the lessened demand. For posts the farmers pre- 
fer the White Oaks and Locust. The .scarcity of these materials 
often forces them to use Chestnut. The county's supply of Locust 



308 



THE FORESTS OF CECIL COUNTY 



was never large and the White Oaks are so constantly drawn on for 
various uses that the supply is always low. 



CHARCOAL AND CORDWOOD. 



Cordwood is the principal forest crop of the county. Owing to the 
cheapness of coal and its greater convenience for domestic use, the 
amount of wood used for fuel (Fig. 24) is small. The greater part 
of the cordwood cut is made into charcoal, for use by the Prineipio 




Fig. 24. Cordwood for domestic use. Elk Neck. 

Forge Company. This company's annual consumption is from 
325,000 to 350,000 bushels. Charcoal burning has been practiced 
in this region for over fifty years (Plate XXX, Fig. 2). Whether 
the local supply of timber for charcoal will keep pace with the de- 
mand is mainly a question of protecting the forest from fire. 



Forest Fires. 
Forest fires are responsible for the present poor condition of the 
Barrens timber. The charcoal burner, in cutting over a tract, 



MARYLAND GEOLOGICAL SURVEY 309 

removes all material an inch or more in diameter as shown in figure 
24. The kilns are built on the tract, and during the process 
of burning, or soon after, fire catches in the dry tops and 
refuse left on the ground and spreads over the cutting. If condi- 
tions are favorable, fire often spreads to the surrounding woods. 
Few of the cut-over areas escape fire, and many are repeatedly 
burned. The sprouting stumps are either killed or injured, and the 
resulting stand is very open. Many inferior species are thus allowed 
to come in, noticeably Mountain Laurel and Scrub Pine, neither of 
which makes good charcoal. 

The Barrens are capable of producing 25 cords per acre. Where 
good stands of Oak and Chestnut are found that much is cut. The 
present average production is seven cords, or less than one-third of 
what it should produce. This is the result of fires. If thinning by 
fire goes on, it will be impossible in the near future to burn charcoal 
profitably in the county. 

Although fires are not common in the shore-timber, they are espe- 
cially noticeable where ties and telegraph poles have been cut. The 
slash left from such cuttings on these areas usually catches fire and 
results in great damage to the future crop. 

Fire Protection. 

The only measure to insure fire protection to the forests of the 
county is the awakening of a sentiment among the farmers that will 
not tolerate carelessness in regard to fire. Measures for the protec- 
tion of these forests can be easily devised, but it will be useless if the 
Cecil land-owners do not care to see them enforced. 

The owners of forest lands seldom realize their loss when a. fire 
occurs. This is the reason for their indifference. If a. crop of hay 
is burned, the owner appreciates his loss. The crop represents to 
him the money value of his labor. If the woodland, in young 
sprouts, is burned and the crop is so thinned that at the time of cut- 
ting 100 acres yield $1000 instead of $3000, the owner's loss of 
$2000 is a future one and is not appreciated. 

The growing crop requires no outlay of time or money, and is 



310 THE FORESTS OF CECIL COUNTY 

therefore considered valueless until the trees reach cordwood size. 
The wood crop is inure often considered a Lucky find or a gift than 
a constant source of revenue to be cared for and protected. The man 
who sets fire to a field crop is considered a criminal and is punished 
by law. lie who burns a wood crop may boast of it openly without 
censure. The loss in the first case may he $200, in the second, 
$2000. As soon as the farmers realize their loss from forest fires 
they will protecl their hinds and enforce fire laws. 

Future of Forests. 

The present condition of Cecil county forests is the inevitable re- 
sult of long abuse and neglect. The better soils of the county were 
once covered with magnificent forests of White Oak and Chestnut on 
the uplands, and of Tulip-tree, Black Walnut, and Hickory along 
the streams. To-day there are only a few defective remnants of 
these forests. 

EARLY CONDITION. 

The steady decline of the forest resources of Cecil comity i- easily 
explained. The earliest settlers cleared small areas of level land 
near the shores of the Bay and millions of feet of choice Oak were 
cut and burned. Year by year new settlers came and cleared forest 
land; the older settlers enlarged their fields, arid so the forest receded 
from the more desirable farming regions. 

As the population of the county increased, timber for ships, lor 
buildings, and for export was demanded, and the choicesl tree- con- 
venient to the watercourses were removed. Consumption and prices 
increased, and the lumbermen went farther and farther from the 
water for their logs. Soon even the remoter parts of the county 
were stripped of their besl timber, and as prices continued to rise 
the materia] left by the tirst loggers was finally consumed. The in- 
crease of population resulted in the clearing of all good agricultural 
land in the county, and the only timbered areas left were -trips along 
the streams and bay-shore, or on the high hills and poor soils unfit 
for cultivation. These are the land- now occupied by forests. 



MARYLAND GEOLOGICAL SURVEY. 



CECIL COUNTY, PLATE XXIX. 




FIG. 1— BLACK CHERRY, RED CEDAR, AND SASSAFRAS. 




FlG. 2.— SCRUB PINE ON LAND ONCE CULTIVATED. 



ROADSIDE TREES. 



MARYLAND GEOLOGICAL SURVEY 311 

Only the growth of the vigorous Chestnut and Tulip-tree, persist- 
ent under the harshest treatment, makes it possible to obtain desirable 
material. These species sprout readily from the stump and grow 
rapidly (Plate XXVIII), and have therefore, in a measure been able 
to hold their own. The fact that the Tulip-tree bears seed at an 
early age has also been an important factor in its survival. "White 
Oak has practically disappeared from the greater part of the county. 
being replaced by the faster growing Red and Black Oaks. The 
gums, Red Maple, and Scrub Pine are creeping in, in ever-increasing 
proportions, and with them many other undesirable species. 

PRODUCING CAPACITY. 

Before suggesting a treatment for the improvement of Cecil county 
forests, the present capacity of the different sections for timber pro- 
duction should be discussed. 

The slow growth and small size of the trees of the Barrens (Plate 
XXVI) limit that region to the production of cordwood. The trees 
of the shore-timber, however, grow rapidly and reach sizes suitable 
for lumber. The depleted condition of the shore forest makes it 
impossible to determine by measurement their possible acre yield. 
The following table gives the present possible yield of the better 
stands if the material produced were fit for lumber. The figures in 
the column under " board feet " are the lumber equivalents of the 
figures under " cords." These cord figures are taken from table on 
page 299. 

TABLE SHOWING POSSIBLE YIELD OF SHORE-TIMBER. 

Average stand Stand on 15,000 
per acre. acres. 
Species. , . , , . 

Cords. Board Feet. Cords. Board Feet. 

Chestnut 3.64 3,151 54,600 47,265,000 

Red and Black Oaks 2.70 2,395 41,400 35,925,000 

Chestnut Oak 2 .04 1,751 30,600 26,265,000 

White Oaks 1.81 1,503 27,150 22,545,000 

Tulip-tree 81 693 12,150 10,395,000 

Other species. 3.93 3,417 58,950 51,255,000 

Average of all species 14.99 12,910 224,850 1 93,650,000 



312 THE FORESTS OF CECIL COUNTY 

This table shows a stand of 193 million feet of lumber for the 
shore woodlands if the better stands were present over the entire 
area. Substract from this the 51 million feet of inferior material 
under " Other Species " and the total merchantable stand would be 
142 million feet of lumber. It is probable that, if the better stands 
were made to produce full crops and these full crops were found 
over the entire area of the shore-timber, the merchantable stand 
would be over 200 million feet of lumber. 

The possible yield for the Barrens timber, if we consider 30 cords 
a full crop, would be 600,000 cords. Twenty-five cords per acre are 
now cut from unburnt areas, so that the estimate of 30 cords per 
acre is not high. 

IMPROVEMENT. 

There are three questions of prime importance to Cecil forest 
owners: 

1. Improvement of the composition of existing stands. 

2. Improvement of quality and quantity of material produced. 

3. Growth of improved stands on all forest-producing areas unfit 
for agriculture. 

To improve the composition of the stands, they must first be pro- 
tected from fire. At the time of cutting, seed trees of the desired 
species should be left to reproduce their kind. These trees should 
be selected from the best found on the area and should, if possible, 
be in seed-bearing when the cutting takes place. Five to ten trees 
of each species desired should be left and they should be distributed 
evenly over the areas and not in groups. In cutting desirable spe- 
cies which sprout readily from the stump, care should be taken to 
insure a good sprout growth. The cutting should take place in the 
fall or winter and the surface of the cut should be slanting to pre- 
vent a rapid decay of the stump before the sprouts are Avell estab- 
lished. An opposite course may be taken with undesirable species. 
If the cutting takes place in the summer and the tops are piled on 
the stumps and burned, no sprouts will appear. All defective trees 
(Plate XXVIII, Fig. 1) should be classed with inferior species and 



MARYLAND GEOLOGICAL SURVEY. 



Cecil county, plate xXX. 




Fig. 1.— making a kiln. 




"Fig. 2.— BURNING a KILN. 



CORDWOOD FOR CHARCOAL. 



MARYLAND GEOLOGICAL SURVEY 313 

removed with them, their place to be taken by thrifty young sprouts 
or seedlings. The trees to remain for a crop on the Barrens are 
Chestnut, and the Red, Black and White Oaks. The main crop of 
the shore-timber should come from Tulip-tree, White Oak, Chestnut 
Oak, Chestnut, White Ash, Black Walnut, and Mockernut Hickory. 
A supplemental crop may come from the other Oaks, Ashes, and 
Hickories, the Elms, Locust, and Dogwood. 

After the composition of a stand has been improved by the re- 
moval of the weeds and the starting of a good crop, the quality and 
quantity of the desired crop must be considered. This is simply de- 
ciding on the cultivation necessary to produce the largest possible 
amount of good material. If a cordwood crop is grown, each acre 
should have enough trees to shade the ground and prevent its dry- 
ing; surface fires must be kept out, as the litter helps to retain the 
moisture of the soil. The shade and litter are essential to the best 
growth of the trees. For the cordwood crop the stands should be 
even-aged, maturing, like grain crops, at one time, giving a clean 
cut, and thus lessening the cost of production. The cordwood crop 
may be compared to the grass or small grain crops, both are started 
and left to themselves until the time for cutting. A lumber crop, 
like a special agricultural crop, tobacco, for instance, requires con- 
stant care from planting to maturity, in order to produce the desired 
quality and quantity of material. Only the general needs of a lum- 
ber crop may be mentioned here. 

Litter and shade are as important for the lumber crop as for cord- 
wood. Tall trunks, clear of limbs, make the best lumber, and to 
produce these the trees must stand very close in their youth (Plate 
XXVIII, Tig. 2). The lower limbs die in the shade and drop early, 
and the young trees grow tall and straight. After the clear boles, 
or trunks, are secured, the stands must be thinned to allow the 
trunks to increase in diameter. Several thinnings may be neces- 
sary during the life of a crop. If we start with 1000 small 
trees per acre, there may be room for only 200 large trees 
when they are ready to cut. In thinning, the 800 trees must be re- 
moved. The early thinnings will furnish fuel, posts, and rails, and 



yi-i THE FORESTS OF CECIL COUXTY 

the later ones, ties, telegraph poles, pulpwood, and some lumber. It 
will thus be no longer necessary To destroy entire woods (Fig. 24) to 
obtain these materials, as is common to-day. 

These suggestions for growing and cultivating a crop of timber 
are easily followed on lands where a good forest growth is found 
(Plate XXVII). On areas with only a scattered growth of inferior 
trees or brush the problem of growing an improved stand is often 
a difficult and costly one to solve. There are thousands of 
acres of land in the county suited to forest growth and un- 
suited to agriculture. These lands, producing less than a cord of 
wood per acre, represent idle capital which should bear interest in 
the form of wood crops. To establish a crop, many of these areas 
will have to be seeded or planted. This method of starting forests is 
expensive if undertaken on a large scale. Most of the untimbered 
areas of Cecil county are small and are scattered through the farm 
lands. If, each winter, when the work is slack, the farmers would 
plant a portion of their waste lands with trees, a good crop could be 
started with but little loss of time and money to the owners. Locust, 
Tulip-tree, White Ash, Black Walnut, and White Oak are suggested 
as suitable for this planting. Either seed or young trees may be 
used. The area of the shore-timber would he doubled if all area- 
unfit for cultivation were planted with forest trees. 

It Is believed that if the forest land in Cecil county were properly 
treated it would yield annually a neat sum from the sale of material 

and each succeeding year see its value increased; the w L-consuming 

industries of the county could be supplied with home-grown material; 
money which now leaves the county would remain and add to it- 
wealth; lumber industries would spring up and give employment to 
men in the winter months when work is scarce; and the county would 
thus be able to support an increased population and add materially to 
the resources and prosperity of the State. 



INDEX 



Abbe, Cleveland, Jr., 61. 

Adams, F. D., 116. 

Adams, W. C, 116. 

Adams, W. H., 56. 

Agricultural conditions in Cecil 

county, 227. 
Aiken, 99, 181, 182. 
Alexander, J. H., 35, 51, 52, 219. 
Alsop, Geo, map by, 33. 
Amphibole-schist, 92. 
Amphibolite, 93. 
Analysis of Cecil loam, 231. 
Analysis of Cecil mica loam, 236. 
Analysis of Conowingo barrens, 238. 
Analysis of Conowingo clay, 239. 
Analysis of diabase, 141. 
Analysis of feldspar, 129. 
Analyses of gabbro, 124. 
Analysis of gneiss, 118. 
Analysis of hornblende, 120. 
Analyses of mica-gneiss, 116. 
Analysis of micro-granitic dikes, 

139. 
Analysis of norite, 128. 
Analysis of Port Deposit granite, 

199. 
Analysis of pyroxenite, 133. 
Analysis of Sassafras loam, 241. 
Analysis of serpentine, 138. 
Analysis of stoneware clay, Bacon 

Hill, 208. 
Analysis of stoneware clay, Carpen- 
ter Point, 209. 
Analysis of Susquehanna clay, 248. 
Analysis of Susquehanna gravel, 244. 
Analysis of washed kaolin. 214. 
Appleton, 114, 220, 234, 236. 
Aquia formation, 149, 164, 177. 
Areal distribution and character of 

the crystalline formations, 87. 
Areas of the different soils, 230. 
Arundel formation, 149. 
Atlantic Coastal Plain district, 

drainage of, 66. 



Atlantic Coastal Plain region, 
structure of, 68. 

Atlantic Coastal Plain region, to- 
pography of, 64. 

Atkinson's cut, kaolin at, 216. 

Avondale, Del., 105. 



Back Creek, 28, 33, 67, 162. 

Bacon Hill, 166, 206, 208. 

Bagg, R. M., 44. 

Bald Friar station, 88, 93, 113. 

Banks, 92, 181. 

Barksdale, 151, 152. 

Barrens timber, 298. 

" The barrens," 75. 

Bascom, F.. 19, 83, 200, 218. 

Basic dikes, 98. 

Basin Run, 85, 115. 

Bauer, L. A., 21, 60, 289, 290. 

Baylor, J. B., 290. 

Bay View, 91, 99, 136, 137, 151, 152, 

167. 
Beach Channel, 208. 
Belvedere, 181. 
Bibbins, A., 21, 31, 42, 43, 60, 150, 

151, 175, 185. 
Bibliography, 49. 
Big Elk Creek, 28, 128, 131. 
Biotite-granite, 91, 117. 
Black Hill, 27, 66, 166, 168. 171, 209. 
Blue Ball, 92. 

Blythedale, 92, 99, 137, 154, 181. 
Bohemia Bridge, 162, 241. 
Bohemia Creek, 28, 33, 67. 158, 160, 

163. 
Bohemia Manor, 239. 
Bohemia Mills, 162, 163. 
Bonsteel, Jay A., 20, 227. 
Booth. Garrett and Blair, 116, 202. 
Boundaries of Cecil county, 25. 
Broad Creek, 153, 206, 216. 
Bromwell, Wm, 118, 199. 
Brongniart, Alex.. 51. 



316 



INDEX 



Brick and terra cotta clays in Cecil 

county, 206. 
Building-stone, 196. 
Bull Mountain, 27, 66, 166, 168, 171, 

209. 
Bureau of Forestry, 295. 
Burnaby, Andrew, 49. 



Cabin John Creek, 157. 

Calciferous, 104. 

Caldwell, H. W., 266. 

Calvert, 89, 93, 289. 

Calvert formation, 149. 

Calvert, magnetic station at, 299. 

Carey, ML, 49. 

Carpenter, Geo. W., 50. 

Carpenter Point, 208. 

Cassidy Wharf, 160, 161, 162. 

Cecil clay discussed, 233. 

Cecil clay, products of, 234. 

Cecil loam, analysis of, 231. 

Cecil loam discussed, 230. 

Cecil loam, products of, 232. 

Cecil mica loam, analysis of, 236. 

Cecil mica loam discussed, 235. 

Cecilton, 241. 

Charcoal and cordwood, 308. 

Cbarlestown, 206, 246. 

Cherry Hill, 151, 152. 

Chesapeake City, 151, 154, 156, 157, 

160, 241, 243, 245, 246. 
Chesapeake group, 149. 
Chestnut Hill, 93, 128. 
Chester, Frederick D., 56, 58, 129. 
Childs, 92, 155, 181, 182. 
Choptank formation, 149. 
Christiania Creek, 235. 
Chrome ore, 96, 221. 
Clark, W. B., 42, 43, 44, 45, 58, 59, 

60, 62. 
Clay of Cecil county, 204. 
Cleaveland, Parker, 37. 
Climate, 249. 

Coastal Plain in Cecil county, 64. 
Coastal Plain rocks, history of, 150. 
College Green, 91. 
Colora, 101. 
Columbia group discussed, 46, 149, 

169. 
Columbia group, sedimentary record 

of, 179. 
Commercial trees discussed, 304. 
Concord, 241. 



Conifers, list of, 302. 

Conowingo, 94, 100, 102, 113, 121, 
132, 134, 135. 

Conowingo barrens, analysis of soil 
of, 238. 

Conowingo barrens discussed, 236. 

Conowingo clay, analysis of, 239. 

Conowingo clay discussed, 238. 

Conowingo clay, products of, 238. 

Conowingo Creek, 28, 34, 79, 86. 

Conowingo, flint mill at, 217. 

Cook, Geo. H., 41, 44. 

Conrad, T. A., 45, 53. 

Cordwood, 308. 

Cowden, Wm. L., 210. 

Crystalline formations, areal distri- 
bution and character of, 87. 

Crystalline formations, petrography 
of, 113. 

Crystalline formations, structure 
and age of, 103. 

Crystalline rocks of Cecil county 
defined, 84. 

Crystalline rock-forming stage, 71. 

Crystalline rocks of the Piedmont 
Plateau, 39. 

Crystalline rocks, sedimentary re- 
cord of, 173. 

Crystalline rocks, summary of, 142. 

Curran, H. M., 21, 295. 

Cypress stumps, 184. 

D. 

Daily, monthly and annual range of 

temperature, table, 256. 
Dale, T. Nelson, 84. 
Dana, E. S., 58, 96. 
Darton, N. H., 42, 44, 45, 47, 58, 59, 

60. 
Day, D. T., 57, 58, 59. 
Description of Magnetic stations, 

289. 
Dean, I. R., 216. 
Desor, E., 53. 
Diabase, 100, 140. 
Diabase, analysis of, 141. 
Dike rocks, discussed, 135. 
Dikes, micro-granitic, 139. 
Dike rocks and other intrusives in 

the granite-gneiss, 97. 
Discharge measurements on Octo- 

raro Creek, 271, 272. 
Discharge of Susquehanna river at 

Harrisburg, 284. 



INDEX 



317 



Distribution of trees, 304. 

Dixon, Jeremiah, 34. 

Doe Run, 105. 

Dorsey, C. W., 20, 227. 

Drainage, 297. 

Drainage of the Atlantic Coastal 

Plain region, 66. 
Drainage of the Piedmont Plateau 

region, 70. 
Ducatel, J. T., 35, 39, 51, 197. 
Duffy Creek, 164. 
Dunlap, Thos., 54. 
Durand, Elias, 51. 

E;. 

Earlville, 162. 

Eastern Shore district of Cecil 

county, 65. 
Eder, 211. 

Egg Hill, 152, 154, 155, 166, 167. 
Elk Neck, 27, 64, 66, 75, 155, 166, 168, 

170, 171, 206, 209, 211, 243, 297, 

305. 
Elk River, 28, 33, 34, 64, 67, 68, 70, 

154, 155, 183. 
Elkton, 43, 65, 67, 68, 87, 111, 128, 

153, 181, 182, 183, 206, 218, 239, 

243, 245, 289, 290, 292, 306. 
Elkton clay discussed, 245. 
Elkton clay, products of, 246. 
Emerson, B. K., 84. 
Eocene in Cecil county, 164. 
Eruptive rocks, age of, 108. 
Evans, N. N., 116. 
Extremes of temperature, 254. 

F. 

Fair Hill, 93, 114. 

Farmer, Jos., 219. 

Farrer map of Chesapeake Bay, 32. 

Fassig, O. L., 20, 249. 

Feldspar, 96, 217. 

Feldspar, analysis of, 129. 

Fencing, material for, 307. 

Finch, F., 249. 

Finch, J., 37, 51. 

Fire-clays, 210. 

Fire protection, 309. 

Fisher, R. S., 53. 

Fish House clay beds, 193. 

" Flint stones," 102. 

Foley, John, 295. 

Fontaine, W. M., 43, 57. 

Ford, J. H., 211. 



Forests, 295. 

Forests, early condition of, 310. 

Forest fires, 308. 

Forests, future of, 310. 

Forests, improvements to, 312. 

Forest-producing capacity of Cecil 

county, 311. 
Forest trees, 302. 
Forest types, 298. 
Fossils in Navesink marls, 161. 
Fossils of Patapsco formation, 155. 
Fossils of Patuxent formation, 153. 
Fossils of Raritan formation, 157. 
Fossils in the Talbot formation, 173. 
Founding of Cecil county, 26. 
Foys Hill, 27, 66, 154, 155, 166, 181. 
France, J. R., 250. 
Frazer, Persifer, Jr., 55, 104. 
Fredericktown, 157, 162, 164. 
Freeze, Simon, 197. 
Frenchtown, 91, 99, 117, 136, 181, 

196, 198, 203. 
Fruit industry in Cecil county, 229. 
Furnace Creek, 67. 
Future of forests, 310. 

Gk 

Gabb, W. M., 53. 

Gabbro, 92, 121, 128. 

Gabbro, analyses of, 124. 

Gabbro as road material, 224. 

Galbreath, A. F., 256. 

Gannett, Henry, 272. 

Garnet, 115, 116. 

Gee, Joshua, 220. 

Genth, F. A., Jr., 116, 141. 

Geographic and geologic relations, 
84. 

Geographic research in Cecil county, 
32. 

Geologic research in Cecil county, 
36. 

Geological record, interpretation of, 
173. 

Geological terms, glossary of, 143. 

Geology of Coastal Plain forma- 
tions, 149. 

Geology of the crystalline rocks, 83. 

Georgetown, 67. 

Gibson, Benj., 222. 

Gilbert, G. K., 43. 

Gillmore, Q. A., 54, 201. 

Gilpin Rocks, 99. 

Glossary of geological terms, 143. 



318 



INDEX 



Gneiss, analysis of, 118. 

Goat Hill. 96. 218. 

Gold in Cecil county, 222. 

Granite at Frenchtown, 204. 

Granite-gneiss, 99. 

Granite-gneiss, described, 90. 

Granite-gneiss, petrography of, 117. 

Granite as road material, 225. 

Gravel as road material, 225. 

Cray & Sons, 203. 

Grays Hill, 27, 65, 75, 93, 128, 129, 

131, 181, 206, 233, 246. 
Griffith, Dennis, 35. 
Grimsley, G. P., 40, 59, 83, 111, 118, 

120, 121, 136, 137. 
Grosh, Warren, 208. 
Grove Point, 67, 157, 158, 159, 160. 

H. 

Haines, 104, 113. 

Hall, James, 104. 

Hance Point, 210, 211. 

Happy Valley Branch, 85, 98. 

Harducoeur. C. P.. may by, 34. 

Hardwood trees, list of, 303. 

Harriats farm, 161. 

Harrisville, 91, 112, 119, 126, 133. 

Havre de Grace, 111. 

Hayden, H. H., 37. 

Heilprin, A., 45. 

Hematite, 97. 

Herrman, Augustin, 33. 

Higgins, Jas., 53, 54. 

Highest observed temperatures, 

table, 255. 
Hilgard, 46. 
Hill, R. T., 43, 59. 
Hillebrand, W. F., 116, 120, 124, 133, 

138. 
Historical review, 31. 
History of geographic research, 32. 
History of geologic research, 36. 
Hobbs, W. H., 84. 
Hog Hills, 27, 66, 166, 168, 170, 181. 
Hollick, A., 43. 
Hooper farm, kaolin at, 215. 
Hornblende, chemical analysis of, 

120. 
Hornblende, biotite-granite, 119. 
Hornblende-gabbro, 92, 121. 
Hornblende-granite, 91. 
Hunt, T. Sterry, 116. 
Huntington, J. H., 56. 
Hydrography of Cecil county, 263. 
Hypersthene-gabbro, 92, 125. 



Igneous intrusives, 90. 

Igneous works, classification of, 143. 

Interpretation of the geological re- 
cord, 173. 

Intrusives in the gabbro belt, 100. 

Iron Hill, 25, 93, 128, 129, 130, 181, 
216, 218. 

Iron Hill station, 83, 93, 128, 129. 

Iron ore, 218. 

" Ising-glass soil," 90. 



Jackson, kaolin at, 217. 
Johannsen, A., 21. 
Johnson, Arthur N., 61. 
Johnston, Geo., 26, 55, 219. 

K. 

Kaolin discussed, 211. 

Kaolin, analysis of, 214. 

Keach, J. E., 295. 

Kenmore Pulp and Paper Company, 

295. 
Keyes, C. R., 50, 59. 
Keyser, Wm., 59, 219. 
Klondike Gold Company, 97, 223. 
Knight Island, 162. 
Knowlton, F. H., 60. 
Kunz, G. F., 56. 



Lafayette formation discussed, 149, 

165. 
Lafayette formation, sedimentary 

record of, 178. 
Lafayette stage, 73. 
Lake, Griffing, and Stevenson, 36. 
Lamb, A. L., 250. 
Laurel Hill, 151. 
Lea, Isaac, 45. 
Leeds, 92. 
Leonard, Arthur G., 40, 62, 83, 121, 

125. 
Leslie, 91, 181, 215, 248. 
Lesley, J. P., 55. 
Lewis, H. Carvill, 43, 55. 
Liberty Grove, 89, 101. 
Limonite, 97. 
Lindenkohl, A., 58. 
Little Elk Creek, 28. 
Livermore and Dexter, 50. 
Low, Andrew, 222. 



INDEX 



319 



Lower White Banks, section at, 156. 
Lowest observed temperatures, 

table, 255. 
Lumber production, possibilities of, 

302. 
Lyell, Chas., 53. 

M. 

Maclure, Wm, 37, 49, 50. 

Mac Farlane, J. R., 58. 

Magnesia, 97. 

Magnetic declination, 289. 

Magnetic stations, description of, 
289. 

Marcou, J., 39, 43, 53. 

Marple, M., farm of, 167. 

Marsh, O. C, 43, 175. 

Martenet, Simon J., 36. 

Martin, G. C, 45, 62. 

Maryland Clay Co., 212. 

Maryland Geological Survey, 61, 62. 

Maryland State Weather Service, 
59. 

Mason & Dixon's line, 34. 

Matawan formation, 149, 158. 

Mather, E., 275. 

Mathews, E. B., 20, 29, 32, 41, 61, 
84, 395, 198. 

Maulden mountain, 27, 66, 156, 157, 
158, 159, 166, 210. 

McClenahan, E. D., 197. 

McClenahan Granite Co., 203. 

McCormick, Jas. O., 249. 

McCullough Iron Co., 220. 

McGee, W J, 42, 43, 45, 46, 47, 56, 
57, 58, 169. 

McKinneytown, 211. 

McKinseys Mill, 128. 

Mean monthly and annual tempera- 
ture, table, 253. 

Mechanics Valley, 99, 216. 

Megredy, Daniel, 197. 

Meridian line, description of, 290. 

Meridian line, instructions for us- 
ing, 290. 

Merrill, G. P., 58, 61, 237. 

Meta-gabbro, 92, 93, 121, 140. 

Meta-peridotites, described, 93. 

Meta-pyroxenites, described, 93, 100. 

Meta-rhyolites, 98, 136. 

Mica-gneiss, age of, 103, 108. 

Mica-gneiss, chemical analyses of, 
116. 

Mica-gneiss, described, 88. 

Mica-gneiss, petrography of, 113. 



Micro-granitic dikes, 139. 
Micro-granitic dikes, analysis of, 

140. 
Middle Neck, 239. 
Miller, B. L., 31, 151. 
Miller, F. R., 295. 
Mineral resources, 195. 
Mitchell, Samuel L., 50. 
Monthly discharge of Susquehanna 

river, 282, 283, 286, 287. 
Monmouth formation, 149, 159. 
Monroe, Chas. E., 56. 
Morton, Samuel G., 38, 50, 51. 
Mount Pleasant, 238. 

H". 

Nagle, C. M., 275. 

Navesink marls discussed, 160. 

Navesink marls, fossils in, 161. 

Neocene in Cecil county, 165. 

Newark shale, 194. 

Newberry. J. S., Prof., 42. 

" Niggerheads," 233. 

Non-feldspathic rocks, 132. 

Norfolk sand discussed, 241. 

Norfolk sands, products of, 242. 

Norite, 92, 125. 

Norite, chemical analysis of, 128. 

Normal temperatures and depar- 
tures therefrom, 252. 

Northeast, 87, 119, 152, 171, 182, 211, 
212, 219. 

Northeast, analysis of clay from, 
214. 

Northeast Creek, 28, 119. 

Northeast, kaolin at, 212. 

Northeast River, 34, 67. 

0. 

Oakwood, 94, 100, 113, 133. 

Octoraro Creek, 28, 34, 78, 86, 102, 
111, 121, 127, 135, 218, 263, 265, 
266, 272. 

Onion, Stephen, 220. 

Operators in Cecil county, list of, 
225. 

Ordinary Point, 160. 

Origin of the streams of the Pied- 
mont Plateau, 78. 



Page, Chas. G., 202. 
Parmunkey group, 149. 
Parke Bros., 220. 



320 



INDEX 



Patapsco formation discussed, 149, 

153, 175. 
Patapsco formation, sections in, 154. 
Patapsco formation, fossils in, 155. 
Patuxent formation discussed, 149, 

151, 175. 
Patuxent formation, section in, 153. 
Paul, E. G., 266, 275. 
Peach Bottom slate belt, 103, 104, 

107. 
Pegmatite veins, 101. 
" Pensauken " formation, 194. 
Peridotite discussed, 133. 
Perryville, 83, 91, 97, 206, 215, 239. 
Petrography of the crystalline for- 
mations, 113. 
Physical features of Cecil county, 

25. 
Physiography of Cecil county, 63. 
Piedmont Plateau, drainage of, 70. 
Piedmont Plateau, origin of the 

streams of, 78. 
Piedmont Plateau, structure of, 71. 
Piedmont Plateau, topography of, 

69. 
Pilot, 97, 239. 
Pirsson, L. V., 141. 
Pivot Bridge, 161, 163. 
Pleasant Grove, 222. 
Pleasant Hill, 217. 
Pleistocene in Cecil county, 169. 
Plum Creek, 207, 248. 
Pond Creek, 160, 184. 
Poplar Point, 153. 
Port Deposit, 40, 67, 86, 98, 117, 136, 

140, 195-205, 250. 
Port Deposit Bridge Company, 197. 
Port Deposit granite, analysis of, 

199, 200. 
Port Deposit granite, test on, 202. 
Port Deposit granite, strength of, 

201. 
Port Deposit granite quarries, 196. 
Porter Bridge, 100, 111, 119, 121, 124. 
Potomac group, 149, 151. 
Potomac group, sedimentary record 

of, 174. 
Precipitation, table, 258, 260. 
Preface, 19. 

Pressey, H. A., 20, 263. 
Principio, 91, 119, 182, 206, 244. 
Principio Company, 220. 
Principio Creek, 28, 119, 136, 155, 

166. 



Principio Forge Company, 308. 
Principio Furnace, 87, 99, 220. 
Pulpwood, 306. 
Pumpelly, R., 56, 84. 
Pyroxenite, analysis of, 133. 
Pyroxenite, discussed, 132. 

Q. 

Quartz-hornblende-gabbro, 92, 121. 
Quartz-monzonite, 117, 119. 

B. 

Rainfall, 257. 

Rancocas formation, 149. 

Raritan formation discussed, 149, 

155. 
Raritan formation, fossils of, 57. 
Raritan formation, section in, 156. 
Rating table for Susquehanna river, 

291. 
Red Bank sands discussed, 162. 
Reid, Harry Fielding, 61. 
Ries, Heinrich, 62, 204, 207, 208, 211, 

212. 
Riggs, analysis by, 129. 
Rising Sun, 87, 96, 101, 112, 221, 232. 
Rising Sun, magnetic station at, 289. 
Roach Point, 210. 

Road materials in Cecil county, 223. 
Roberts, D. E., 60. 
Rock Run, 85, 97. 
Rock Springs, 27, 70, 85, 93, 97, 218, 

221. 
Rogers, H. D., 53, 54. 
Rowlandsville, 120. 
Russell, Wm, 219. 
Rustin, John, 220. 



St. Mary's formation, 149. 

Salisbury, R. D., 48, 193, 194. 

Sassafras, 165. 

Sassafras loam, analysis of, 241. 

Sassafras loam discussed, 239. 

Sassafras loam, products of, 241. 

Sassafras Neck, 239, 242, 297. 

Sassafras River, 33, 34, 45, 160. 

Scharf, J. Thomas, 58. 

Schooley Peneplain stage, 72. 

Scotchman Creek, 160-162. 

Scott, Joseph, 49. 

Section at Foys Hill, 154. 

Section at Lower White Banks, 156. 

Section at Maulden Mountain, 156. 



INDEX 



321 



Section in Patapsco formation, 154. 
Section near Principio Creek, 155. 
Section at Pumping Station Well, 

Elkton, 153. 
Section in Raritan formation, 156. 
Section at Turkey Point, 172. 
Section in Wicomico formation, 172. 
Sedimentary record of Aquia forma- 
tion, 177. 
Sedimentary record of Columbia 

group, 179. 
Sedimentary record of the crystal- 
line rocks, 173. 
Sedimentary record of Lafayette 

formation, 178. 
Sedimentary record of Potomac 

group, 174. 
Sedimentary record of the Upper 

Cretaceous, 176. 
Serpentine, 93, 94, 131, 134. 
Serpentine, analysis of, 138. 
Shaler, N. S., 54. 

Shattuck, G. B., 19, 31, 44, 62, 63, 149. 
Shore timber, 300. 
Simpcoe, J. F., 208. 
Simpress, Chas., 209, 210. 
Singerly, 155, 181. 
Singleton, H. K., 56. 
Sioussatt, St. George L., 61. 
Slate, 103. 

Smith, Anthony, 34, 197. 
Smith, Capt. John, 26, 32, 49, 218. 
Smock, J. P., 55, 56. 
Snowfall, 260. 
Snowfall, monthly and annual depth 

of, 261. 
Soapstone, 93. 
Soils of Cecil county, 227. 
Soil formations, 229. 
Southern gabbro belt, 128. 
Steatite, 95. 

Stone Run, 121, 124, 222. 
Stoney Run, 91. 

Stoneware clay, analysis of, 208, 209. 
Stoneware clays in Cecil county, 

207. 
Streams of the Piedmont Plateau, 

origin of, 78. 
Structural relations and age of the 

crystalline formations, 103. 
Structure of the Atlantic Coastal 

Plain, 68. 
Structure of the Peidmont Plateau, 

71. 
Sud worth, G. B., 295. 
21 



Sunderland formation, 149, 170, 181. 

Sunderland stage, 74. 

Sunderland terrace, 182. 

Susquehanna clay, analysis of, 248. 

Susquehanna clay discussed, 246. 

Susquehanna clay, products of, 247. 

Susquehanna gravel, analysis of, 
244. 

Susquehanna gravel, discussed, 243. 

Susquehanna gravel, products, of, 
244. 

Susquehanna, origin of name, 86. 

Susquehanna river, 34, 47, 70, 86, 
263, 272-287. 

Susquehanna river, monthly dis- 
charge of, 282, 283, 286, 287. 

Sutton, Geo. W., 215. 

Summary of the crystalline rocks, 
142. 

Swank, J. M., 56, 219. 

Swedenborg, Emanuel, 49. 

Sylmar, 97, 101, 112, 132, 133, 218. 

T. 

Table showing average daily, 
monthly and annual range and 
absolute monthly and annual 
range of temperature, 256. 

Table showing daily gage height of 
Octoraro Creek, 268, 271. 

Table showing daily gage height of 
Susquehanna river, 276, 277, 278, 
279, 280. 

Table showing highest observed 
temperatures, 255. 

Table showing lowest observed tem- 
peratures, 255. 

Table showing magnetic declina- 
tions, 289, 292. 

Table showing mean monthly and 
annual temperatures, 253. 

Table showing monthly and annual 
depth of snowfall, 261. 

Table showing monthly discharge 
of Octoraro Creek, 267. 

Table showing possible yield of 
shore timber, 311. 

Table showing precipitations, 258. 

Table showing relative abundance 
of species in the Barrens timber, 
299. 

Table showing the relative abund- 
ance of different species in the 
shore timber, 301. 



322 



INDEX 



Table showing variations in tem- 
perature, 251, 252. 
Talbot formation, 149, 172, 187. 
Talbot formation, fossils in, 173. 
Talbot stage, 76. 
Telegraph poles, 307. 
Temperature conditions, 250. 
Temperature, extremes of, 254. 
Terra cotta clays of Cecil county, 

206. 
Tertiary formations of Cecil county, 

45. 
*' Texas," 96. 

Theodore, 92, 151, 152, 166. 
Thiess, A., 216. 
Thorpe, Henry W., 249. 
Timber, 298. 
Timber, uses of, 305. 
Toner, Jos. M., 54. 
Topographic description of Cecil 

county, 64. 
Topographic history, 71. 
Topography and soil, 297. 
Topography of Atlantic Coastal 

Plain, 64. 
Topography of Piedmont Plateau, 

69. 
Town Point, 26. 
Truck in Cecil county, 228. 
Turkey Point, 67, 154, 155, 157, 171, 

172. 
Tyson, Isaac, Jr., 96, 221. 
Tyson, Philip T., 39, 44, 52, 54. 

TJ. 

Uhler, P. R., 42, 44, 56, 57, 58. 

I 'pper Cretaceous formations dis- 
cussed, 44, 157. 

Upper Cretaceous, sedimentary re- 
cord of, 176. 

U. S. Coast & Geodetic Survey, 21, 
35, 289. 

U. S. Department of Agriculture, 21. 

U. S. Geological Survey, 21, 275. 



U. S. Weather Bureau, 21. 
Uses of timber, 305. 

V. 

Van Rensselaer, Jer., 38. 
Vanuxem, L., 38. 
Veazie Neck, 183. 

W. 

Waba, A. O., 295. 

Wakefield Fire Brick Co., 211. 

Ward, L. P., 42, 43, 60. 

Warwick, 239. 

Websterite, 132. 

Weeks, Prank, 217. 

Welch Point, 207. 

West Chester, 105. 

Western Shore district of Cecil 

county, 66. 
White Banks, 156, 157. 
Whitfield, R. P., 42. 
Whittaker and Co., 220. 
Whitney, Milton, 20, 59. 
Wicomico formation discussed, 149, 

171. 
Wicomico formation, section in, 172. 
Wicomico stage, 75. 
Wilbur, F. A., 56. 
Wildcat Point, 88. 
Wildcat Cave, 88. 

Williams, G. H., 40, 57, 59, 108, 136. 
Williamsons Point, 101. 
Wilsons Beach, 210. 
Wissahickon, 106. 
Wolff, J. F., 84. 
Woodlands and forests, 298. 
Woodlawn, 27, 152, 153, 166, 244, 250- 

261. 
Woodlawn, temperature at, 250-253. 
Woods mine, 96. 
Woolman, Lewis, 193. 
Wright, F. B., 31, 150. 



Zion. 100, 232. 





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